Antisemitism on Twitter - It's @_fuck_israel_ again

I've blogged about @_fuck_israel_ before and the anti-Semitic views that he freely espouses. He stepped over a line last week, here's some examples.

First some general anti-Semitic insults:

Secondly some general threats aimed at all Jews:

Thirdly a direct threat aimed at @Adelirose

Finally a direct threat aimed at me

 

If you notice @_fuck_israel_ has abandoned any pretence of not being anti-Semitic and has changed his Twitter handle to fuck-jews. Why does Twitter allow such blatant anti-Semitism and threats against Jewish users of Twitter to be made?