The preacher commenting that homosexuality is a sin does not make him a bigot, it makes him true to the Word. Sorry, but the Bible, which Christians take seriously as the divinely inspired word of God is pretty clear on the subject. If secular politics wish to go another way, they are departing from the Word. Its a very slipperly slope (politically and eternally) to try to suggest that the Church needs to down play their stance on homosexuality in the interest of political correctness.
I do agree, however, that many Christian zealots are rather obsessed with homosexuality as if it were the only sin (where is the equal outrage on greed and divorce, two areas Christ spoke about, where Christ did not speak on homosexuality specifically) This obsession borders on hate for homosexuals for some Christians and even crosses the line for others. So, hate speech from otherwise good intentioned Christians does exist.