Interesting conundrum for Twitter/Facebook etc. What if this idiot posted on Twitter before he committed this hideous act of murder? Would they close shop?

Both those social media services claim they are platforms not publishers. However they exercise a huge amount of control over content like a publisher would. They are painting themselves into a corner.

Also, for those who float the idea that GAB is Mossad controlled. this poses a hard question. Why would they allow this anti Jewish stuff on their platform?