Because facebook is a handy label for all forms of malicious capitalism. And the excesses of malicious capitalism are becoming sufficiently extreme that people are starting to notice. It's much easier to notice this in new technologies rather than old ones you're already comfortable with. So facebook gets the flak, which is deserved but lots of other people avoid it.

Take soft drinks which are terrible for peoples health. Your profit comes from:

1) Convincing people that buying your drink will make them popular & happy. 2) Convincing the government to keep corn subsidies. 3) Convincing everyone that calories in calories out and self control are the _real_ method to health. Our sugar water isn't at fault it's your personal weakness!

We're in a situation where powerful companies use their economic clout to buy off the government and convince the population of falsehoods so they can make more profit.

This isn't new but since we've gotten pretty optimised on at solving genuine human needs (companies vs entropy) is much harder to profit from than fooling suckers into bad choices (companies vs irrational monkey brains).

So now all our most profitable companies largely work to create little anti-competitive fiefdoms and to fool people into harming themselves. So of course people are going to point out that this is terrible and we should probably do something to regulate it's excess.