To me I'd meet Oliver halfway on this topic.
I personally don't think that verbally attacking a group of people on Social Media should see you arrested. And I do agree with Oliver that violent hate crimes should definitely see the thug that committed the offence arrested.
However we do get cases where say a Lesbian woman is getting harassed by a straight guy for being a Lesbian, and he keeps hurling abuse at her, imo that individual should also be arrested for harassment and a hate crime as he would've deliberately targeted her because she's a Lesbian.
Obviously I'm just putting out a hypothetical scenario there (that was also quite long winded) but I hope that you guys understand what I'm trying to say.