Hopefully, they will win the lawsuit. Indeed it is unfair to the developers, participants and all the other people involved in ICOs to ban advertisement on such popular platforms as Facebook, Google, Twitter and Yandex. It's a known fact that without promotion no business can survive nowadays, so they are literally trying to kill the ICO business by those restrictions.
I'm not trying to say that ICO scams should not be banned, but banning all the ICO ads is not how it should be done in the free world.
There's no way they will win this lawsuit, they're a small fish compared to those companies, plus governments are pretty suspicious of cryptocurrencies. On top of that, those companies are free to decide what ads they show to their users, I don't see anything illegal in refusing to work with certain customers (ICO's and crypto services).
What would really be nice though is if search engines stopped giving ad space for phishing sites that mimic exchanges and wallets, since newbies are easily getting tricked by them.