What they can’t do is ban people from their platform and say “the FTC made me do it”, unless the FTC actually made them do it. Since the FTC didn’t actually make them do it, they got a public nastygram from the FTC saying “we didn’t make them do it”.
They have no obligation to support those researchers, but it sure is a bad look blocking them.
Legally they don't have any responsibility to these researchers. They can ban anyone. The argument is that they shouldn't ban these people. That's why they're getting a polite letter rather than any kind of legal action.
Ideally (another should) moral considerations would always apply. External shaming comes into play when you've managed to outrage the moral sense of enough people, or powerful enough people. Yes, this does ultimately come down to social approval, but mediated by whether you can make a moral argument that people respect or not.
With regard to every previous argument we've had on here about Facebook banning people, it comes down to approval or not of the content, conduct, or actors being banned. Only the most extreme people argue that you should be able to post goatse to Facebook (not actually illegal!) without them removing it.
Seriously don't understand why the private company line of argument seems to hold so much sway for some people
I guess I could see an auto-scroller being used to grab ad impressions, and that could count as click fraud… except without clicks what are you left with, “impression fraud”?