They were backed into a corner by complaints from customers and there were no guidelines from governments to handle this issue, so they just implemented a blanket ban on everything.
Don't put everything on the government. I know they do things wrong quite often, but what social media networks did has nothing to do with the government, but more with shitty multinationals threatening to cut off their billions in ad budget. Read
this article, it might help clear things up a bit. In other words, it's more the fear of losing billions in ad revenue and potential legal troubles that made social media networks do so. People keep focusing on ICO's and stuff, but that's not even the problem, it's just the general aspect of crypto as a whole thing which they are looking to get rid of. It has also affected content creators on Youtube, so it's not strictly an attack against crypto. Times are changing, but in some cases not for the better unfortunately.