I'll say this for American non-tolerants like Prof. Youssef. They are not violent and I'm grateful. But, the underlying argument they make is no different now than in the 16th century - demand liberty and religious toleration, but only for themselves.
And, presume that there are gays who agree with him as he says, it would not surprise me because, one, you can find someone of almost every opinion and, two, many people who are stigmatized or loathed learn to loathe themselves. But how can some gays agreeing with him make him right if the majority disagreeing doesn't make him wrong?
The end of the conservative party in Britain? I doubt it. More likely Republicans here will shed the anti-gay rhetoric.