I worked for many years in vector borne disease surveillance. Most of what you have said is wrong or misleading.
DDT based mosquito "eradication" programs never eradicated any mosquito populations, because a single surviving gravid Anopheles mosquito can lay over two hundred eggs at a time. But malaria has a weakness that mosquito borne encephalitis does not have: most strains of Plasmodium have no significant enzootic reservoirs -- that is to say most strains that infect humans, infect humans exclusively. This means if you can eradicate human-to-human transmission, you eradicate the underlying infectious agent.
In the late 40s DDT *was* instrumental in eradicating endemic malaria in the US, but that was through over four million "domestic" treatments -- applications. These are treatments of the *interiors* of homes. In domestic applications, the DDT does not enter the food chain and does not bio-accumulate.
DDT is not magic pixie dust. It's not the only pesticide that works, and it is neither necessary nor sufficient for malaria eradication. It is, however, valuable. It is cheap, effective, and relatively long-lasting, which is a huge boon in domestic applications because it reduces the number of re-treatments you have to do. That same property of longevity makes it a very poor choice for agricultural use.
I attended a number of meetings where the prospect of using DDT for malaria eradication in the third world was discussed. The key problem is that many places where it is needed are desperately poor, and theft is rife. I knew plenty of researchers who had their field equipment stolen; some of them took to putting their computers and backups in a backpack and slept with it to keep from losing their data. There is a high risk of DDT being stolen and diverted to agricultural use, where its drawbacks come into play: under certain conditions it can persist in the soil for years, and it has a high potential to bio-accumulate, so even small concentrations can have effects on predatory animals. Furthermore runoff into water sources in sub-lethal concentrations has a high potential to create DDT resistance in target species including Anopheles, the vector of malaria. That could undermine attempts to eradicate a number of mosquito borne diseases other than malaria. This could have significant effects on attempts to control many mosquito borne diseases, malaria included.
Chemists who create chemicals to save people's lives are not mad scientists and these anti-DDT activists are not all knowing supermen come to save the planet
Well, this is kind of a strawman argument. I've worked with people in the pesticide industry, in public health, and with environmental groups, and as far as I can see the images you mention here are entirely a figment of your own imagination. Everybody who studied this problem understand there are risks and benefits to using DDT, mainly they differ on how they weigh the risks.
In any case, if we knew that domestic DDT applications could eradicate malaria in an area back in 1950, why wasn't it eradicated worldwide? Because there's never been the political will to do that. There has never been a worldwide ban on DDT (which is why they're seeing way up in Tibet), so why hasn't it been eradicated in more places? Because there was never the political will to do it. If the will existed, we could do it, with or without DDT, just with somewhat less initial cash outlay for DDT.
Let me reiterate: DDT is not magic pixie dust. It *does* have potential to reduce the initial *cost* of eradicating malaria (except in SE Asia, where zoonotic forms of Plasmodium exist). But wherever malaria could be eradicated *with* DDT, it could also be eradicated with something else, say with synthetic pyrethrins. Pyrethrins have a very short half-life outdoors, reducing problems of pesticide resistance and bio-accumulation. The main drawback is that they also have a somewhat shorter half-life indoors, requiring more repeat treatments in the eradication phase. That'd still be a bargain in terms of human life.