This is because the definition of "political correctness" is different from person to person. It conveniently drifts so people can think they're against some common problem when in reality some people use it to veil homophobia, and others to complain about postmodernism.
It's a convenient term, but useless. You call someone politically correct and they'll say no. You learn nothing about their position, you only get to engage in some petty name calling. Feels good, right? Maybe we should stick to the factual matters, the specifics of what legislation and culture is too "politically correct" for you.