Yes, but corporations still can't act against the interests of the public. Try making dangerous products. In such cases, the corporation would be making money, their suppliers would be making money and 401(k) accounts would be making money, but it would be dwarfed by the long term costs from people would end up injured. Making money in the short term is not a justification for bad behavior in the least.
Yes, but who defines the best interests of the public? I'm not saying you're wrong, simply playing Devil's Advocate here. True, dangerous products affect all - either directly, by those who are harmed, or indirectly - families who suffer from a loved one's death or injury, etc. Common Social Morality tells us that those products should be blocked, and companies stopped. However, you then get into gray areas - products that can cause harm when used incorrectly, or even when used correctly, but the choice to use them is left up to purchaser.
The problem when trying to use this argument with the Comcast/NBC deal is that the FCC/FTC/etc. have to quantify actual damages - they can't simply say "Well, they might do this or they might do that " and use that as the justification. You can't convict someone (and bear in mind that U.S. Law treats Companies as individuals with individual's rights) of something that they haven't done yet - even if there is some evidence that they might.
If Comcast thinks that its actions related to FCC v. Comcast and other unrelated behavior should have no bearing on its current attempt at acquiring NBC, I assure you that both the FCC and FTC will have something to say about that. Either agency can and potentially even object to or block the sale of NBC to Comcast.
Sure they can - I wasn't saying that they couldn't. But Comcast can, and will, most assuredly, appeal any decision to block the sale. My point was, the FCC/FTC/etc. will most likely loose on appeal - and they have to stop and question if that is the kind of precedent they want to set - appeal our decisions and they'll be overturned if we can't quantify them. What kind of enforcement power would they have then?