Actors can't do without a social network. You can bitch all you want about it, it's become completely impossible in their profession - or almost.
As for the trick of blocking, you must not have been stalked very seriously or very much if that was enough to stop them. In my experience, it can even make things worse - the stalker moves on to other networks (especially professional ones) where you really don't want to see them. Sometimes, not blocking is precisely the right thing to do because it lets you know where the messages are going to land.
In short, enough of the ‘just block / don't care / etc’ rhetoric that half-heartedly accuses people who are victims of online harassment of being whiners.