Slate writer Amanda Marcotte gets to the root of it:
The American right is undertaking a huge project of trying to put right-wing politics beyond criticism by shouting “religious bigotry” any time someone gets in the way of their political agenda. If they can create a consensus that it’s somehow off-limits to criticize teaching that gay people are subhuman as long as you wrap it up in religion, that gives them a huge political advantage. Taken far enough, merely stating out loud in public that you don’t believe gay people are evil could be cause for the fainting couches to be pulled out and accusations that Christians are being oppressed. Sounds ludicrous? Well, consider that we’re currently debating whether or not it’s oppressing Christians to accurately state what’s in the Bible. Anyone who is actually supportive of gay rights shouldn’t be playing along with this feigned umbrage. It won’t stop until opposing anti-gay actions is considered completely off-bounds on the grounds that it’s an attack on religion.