I can't prove it, (and it is highly inflammatory to say), but I would hazard the following guess as to why:
Corporations have intellectual blinders on. They are far too focused on "Beating the other guys" (financially, economically, technologically, legally, and otherwise) that the very concept of enlightened self interest-- Helping others, to promote a better environment, which they also stand to profit from-- is not given proper attention.
Note, the company you work for only considered this charitable solution after it was discovered to be cheaper and with fewer regulatory hurdles than actual electronic waste disposal. (even though these devices will eventually get there, regardless. nothing lasts forever.) Ultimately, the allure of such initiatives at the corporate level has nothing to do whatsoever with improving the community, and everything to do with foisting a cost center onto somebody else. (Disposal fees for the ewaste now are the concern of the charities that repurpose the waste, and of the people who accept the repurposed waste, when those devices actually do catastrophically fail. Granted, this can be after many years of service-- however, they WILL eventually fail, and they WILL require proper disposal at that time. The people paying for the disposal will be the new owners. Not the company you work for.)
The concept of "enlightened self interest" is far too long term for modern corporate culture to even come close to comprehending-- It uses forces that mature over several decades, often at human-generation timescales. That's where the payoffs on recycling like this REALLY happen-- you increase availability of an essential resource, increasing the possible labor pool in 20 to 30 years, as a consequence of the increased availability of the raw equipment needed to foster competency and skill.
Corporations dont like to think this way. They want to think about how they can cheat the system to increase their profits THIS QUARTER; not how they will get competent workers in 20 years. For the latter, they tend to suckle the teat of modern 'free market capitalism' philosophies, and expect to just magically get what they need, without actually investing in the competencies they are going to need later on.
You see this rapaciously happening in the US-- Our BS with H1B visa abuses, massive over-use of foreign workforce, short-sighted erosion of regulatory laws, and so much more. All have the central theme though: Get the money, get it quick before anyone else can, crowd out everyone else-- the market will always provide, it will be OK.
In a sense, what you have done by revealing this to your employer is highly pathological, when taken in this context-- You have enabled them to circumvent a regulatory compliance directive aimed at ensuring proper disposal of their e-waste, by allowing them to redirect that waste flow into the public commons.
Having been discovered and exploited, I would forecast the following, in this order:
1) This will be suddenly become INSANELY popular. Other companies will follow suit.
2) There will be a glut of viable e-waste in the charity network, far outstripping demand. the real nature of e-waste as refuse will rear its head.
3) This glut of ewaste at the charity level will prompt a less savory secondary market, which appropriates these low cost assets and resells them abroad, or in other municipalities-- for a time.
4) regulators, (sadly, often captured by the companies they are supposed to be regulating) will step in, and impose new regulations prohibiting the disposal of ewaste in this fashion. This is because the e-waste is not being disposed of properly/disposal fees cannot be realistically charged to the new endpoint of the refuse chain. Supply to charities will dry up.
5) Ultimately, after an initial boom, there will be less overall availability of perfectly usable recycled electronics than before.
[obligatory: 6) profit]
There is an alternate pathway, of course, depending on how the regulatory agency(ies) of your country react to the sudden increase in "Domestically sourced E-waste".
4a) Regulators, captured by those they regulate, create regulations that exempt domestic e-waste from the same levels of scrutiny that corporate or business generated e-waste are subject to, to ensure that this loophole remains open at the detriment of the environment, which is against their mandate. (See for instance, how the US's EPA handles domestic ewaste.) To keep this loophole to themselves, new barriers to entry to the "Charity" side get enacted, to restrict the number of recycling charities, which are then controlled via exclusive sourcing/supply contracts. This ensures that "early adopters" continue getting the gravy, while new contenders in the marketplace are left in the cold.
5a) The restriction against spontaneous formation of new charities to service genuine public needs results in a net loss for the society, coupled with the environmental ills of poorly regulated e-waste disposal. (landfills full of refined rare earth elements, toxic byproducts of epoxy decomposition entering ground water, etc.)
What *REALLY* needs to happen, but which TOTALLY WONT HAPPEN, is this:
4b) Regulatory agencies allow for corporations and businesses to make such "Charitable donations", but still require those corporations and businesses to pick up the tab for proper disposal of that waste later on, using a registration authority.
5b) this allows e-waste to still enter the charity network, leaves the charity network unfettered in its service of the public, and actually facilitates the operation of the charities in question-- ensuring the best possible operation of those charities-- but also makes this "disposal method" less desirable, or possibly equally desirable to direct disposal. (the costs of future disposal may be difficult to predict, but the current cost of disposal is well known.) This ensures that a large percentage of the commercial ewaste stream is properly handled and treated, reducing environmental impact, while still allowing this waste to be "recycled."
The reason this method will NOT be considered:
It forces commercial producers of ewaste to still be legally responsible for that waste's proper disposal later, which places these producers of waste in a compromising situation; unless they can get some other kickback for contributing to the charity, (such as a tax break) that more than makes up for the amortized risks now associated with the action, it makes the donation of ewaste a non-starter. (This is by design, however-- it prevents the massive glut of ewaste into the charity network.)
As a consequence of the above, "Free market" pundits will decry it as being of the devil, and will actively seek the prevention of such a solution; they favor the initially stated flow of outcomes, because it results in the greatest amount of "market activity", and things like the environment are just "externalities."
Corrupt government officials favor the second stated flow of outcomes, because it ensures a profit stream for early adopters, (which they can be, if they invest early, THEN impose the regs. See how US senators and congresscritters make their fortunes.)
This leaves this much more socially responsible 3rd option out in the cold, as usual.
Getting back to why corporations don't initially "SEE" these things-- they are focused on making the most money they can, as quickly as they can, and externalizing as many costs as they can. Fearing the possibility of my 3rd option (and in addition, other factors such as data security and secure disposal requirements that require complete shredding of the waste) , they shy away from donating ewaste. The actual societal benefits of recycled ewaste in the form of increased domestic labor efficiency are too long term-- and the short term exploitative tactics they are beholden to actually makes their widespread use of this option deleterious to the social good. (a little medicine is good, but too much is toxic. Same here.)