I'm going to be blunt here and say that while PC language can go to far ("thought showers" falls into this category, IMO), language that assumes that right-handedness, whiteness, maleness, and straigtness are the norm, and are good, IS oppressive.
We're all writers, and we know the power of words. The right word in the right place can uphold and uplift, or put down and oppress.
It doesn't take much effort, for example, to use "human" and not "man" when you really do mean all humans. Or to find different ways to speak about right and wrong that don't use black and white as metaphors.
The way we use words is changing, as it has been changing since language was invented. So why are you upset when some people, (who were NOT necessarily American, BTW) realized that words have the power to hurt, and are trying to change the way we speak?
I really don't understand why people complain about PC language. To me, folks who do so seem either to be prejudiced against the groups in question, or people who are unwilling to change simply because they've been told that what they've been doing all along is wrong.