To be fair, I have seen plenty of Spike shippers who go to great lengths to defend him, and Willow shippers who go to great lengths to defend her, and Buffy shippers who... well, you get the idea. I think that's just one of the pitfalls of having a favorite character. I'm not sure it's tied up in having any particular favorite character. We just tend to notice it more when people who have a different favorite character do it.