Having lived in Europe for a long time, you have to understand that anti-semitism and hatred for Israel is not a "thought crime", but a real crime against real people. Against people, and against Jewish institutions like synagogues and cemeteries.
People can think whatever they like, no matter how vile. When they start to put their vile thoughts into action, into assaults, murders, and vandalization of religious sites, it is time to stand up and be counted.
I've also lived in Europe. I once had a neighbor who was threatened with criminal prosecution in the Netherlands for expressing her opinion in her own home that homosexual behavior was deviant and contrary to Christian principles. This is the Europe that Giuliani was exhorting to make its hate crimes more strict.