Freedom of speech in universities, does it exist?

A university campus and especially in a lecture should be a place where freedom of expression and ideas are allowed to flow freely, the reality is though that most Western universities quell freedom of speech, is anything that detracts from freedom of expression and ideas in reality just unacceptable, as without them robust debate cannot occur. in my expeience of university the forbidden categories of free expression where: Any opposition to multiculturalism,objections to gay marriage,support for the state of Israel,criticism of Islam,Any expression of patriotsmand nationalistic pride. If you brought any of the above up you were shouted down,closeddown and even threatened. whats going on in these places ?