Free speech has limits, even in the US. In the UK, we don't have free speech - we just think we do. Equality legislation passed over the past few years outlawed stuff like this. It's "incitement to hatred"; in this case particularly so as he's clearly suggesting gay people ought to be treated as the Nazis treated the Jews (and gays).

I do understand the Christian difficulty with homosexuality but private religious beliefs are not an excuse for this kind of thing.

...Wow, I actually managed a coherent response. Go me!