The UK thought police have no sense of humor - Hammers to be banned for 'anti-semitism' by Jay Knott (11/26/12) ⇌ (Islamophobia/Islamophilia)
It also happens at Ajax in Holland. It even happens between Haifa and Tel Aviv. The point is, to be as offensive as possible. There is a huge gulf between this and actual threats. Israeli football fans are not about to put each other in gas chambers. Neither are English football fans.