I think maybe Facebook and GuGe think that there are some ICO which is a scam that will harm other people's interests, so advertising is prohibited.
It is as if China's stationary ICO transaction is a truth, lack of control, and some criminals are just to cheat the money.
it depends on the person if they wanted to get scammed. you know majority of people are still wise enough and they know whether that thing is a scam or not.
You can only get scammed if you are a lazy person that dont read and do a quick research in regards to your investments. so overall i guess theres nothing to worry about it and these companies and countries shoudnt have ban ico or other crypto related ads in the first place because they arent the ones who can get affected with this issue.