I don't hate Christianity as a whole, there are some Christian movements that I find respectable, which are progressive, open and loving. I may not want to be part of it, but I find such people and churches to be nice and interesting.
I guess I only object to those who think they have the Truth and that people who don't agree with them are sinners, will go to hell, shunned, cut off, etc. There's also sometimes some despicable practices like converting vulnerable people or "curing" homosexuals, etc. To me, this is worthy of opposition.
But my opposition doesn't stop at Christianity, I treat other religions the same if they have terrible practices or beliefs. There's dogmas that must be believed and followed without free thought and that make me feel like something has to said and done.
I'm not opposed to religion, per say, and they're not all equal but I'm opposed to bad ideas that influence people.