"Bigot X isn't a real Christian" is a sentiment that just about any LGBT advocate has seen countless times; and it's particularly prominent at the moment due to the incipient shuffling off of vocal hater Fred Phelps's mortal coil.
The person saying it is almost always themselves a Christian, and objecting to the use of their faith and god as a tool for the hatred or oppression of others. In this case it's LGBT people, but in the past the same dialogue has occurred around blacks, women, and other minority populations.
The problem is, those people are just flat-out wrong.
I'm not remotely interested in getting into a liturgical argument here. For one thing, not ever having been a Christian, I lack the knowledge and credentials to do so. Moreover, the tenets of Christianity are completely irrelevant to the conversation.
Religion and faith in the modern world are matters of self-identity, and it's not for anyone else to impose their religious litmus test on another. If Bigot X says that they are Christian, their co-religionists don't get to declare otherwise. Nor is it their place to speak on behalf of the faith to say that that Bigot X does Christianity "wrong."
Certainly equality-minded Christians can (and in my view should) shout from the rooftops that Bigot X's interpretation and implementation of the teachings of the faith runs counter to what many see as the very foundation of Christianity and the heart of Jesus's word. Honestly, I'd like to see a lot more of that happening when the Phelpses, Barbers, and Fischers of the world open their mouth near a microphone.
But saying "that person isn't really a Christian" is a cop-out. It's what people say when they don't want to be associated with bigots, but also don't want to put themselves out there and be vulnerable by actively refuting bigoted viewpoints on liturgical or cultural grounds.
Believe me, I understand the desire to distance oneself from one's co-religionists. There are people within my own communities of neo-paganism and modern polytheism who espouse views that I find utterly reprehensible, and that run counter to my understanding of the relationship between people and the gods. My faith communities are no stranger to bigots either, and like the Christians, our bigots often have the loudest voices.
But one can't avoid the reality that there is a diversity of beliefs and perspectives within any faith simply by disavowing those we disagree with. I'm not saying that we have to value, or that we shouldn't work from within to change them, or even quiet their voices. Those are internal matters however, distinctly separate from how we interact with those outside of our faiths.
The right to one's identity is at the core of everything the LGBT community holds dear and has fought for over the last half-century. We don't get to take that away from anyone just because we disagree with them.
Christian bigots are still Christian, regardless of how those inside and outside their religious communities may feel about the way they choose to experience and live their faith.