"Many in the West have come to consider anti-Israeli terrorism as acceptable (as righteous resistance to Israeli oppression of the Palestinians and other Arabs). Most Western counter-terror organizations know better, but in places like Europe it’s become more acceptable to hate Israel and support those that do that with terrorism."
It's called the Islamist lobby. As the Muslim population of a country grows, the more influence they will have, and they will use that influence to coerce the country and the culture to take up their own causes. Those who resist face a lot of trouble.