I don’t think that’s true… If one takes the time to educate themselves. And even if they don’t, we all find ourselves in a situation where our mouths get us in trouble. It’s really easy to say “Oh, I’m sorry. I didn’t know that was offensive, I’ll stop saying it” even if you just stop around the person in question. What have we lost by saying that?
For instance, I teach high school. Quite a lot I hear the students use the phrase “retarded”. This is not acceptable. Because I often help out in the special ed departments and our special ed students are wonderful people who try their best with the cross they’ve been given. So, when a student goes “you’re retarded” I say “excuse me, that is a hurtful slur, and it’s not appropriate” and the student usually gives a sheepish look and says “Oh, sorry.” That’s all it takes.
As for people flying off the handle - I can see that. Especially if it’s an honest mistake. People fly off the handle all the time for a myriad of topics (you stole my parking space, you stepped on my shoes, you’re looking at my girl, etc), it’s not a problem that’s restricted to people being offended over “PC issues.”
I don’t think it’s so much that people think others are trying to be hurtful (though in the case of pronouns and bathrooms, some definitely are). It’s more they’re upset that people refuse to acknowledge that they’re causing pain, or, think they can inflict it with impunity. But it definitely comes in levels. Racist old Grandpa who still uses the phrase “the coloreds” is different from someone legitimately not knowing a word is hurtful. Or someone who has learned that a word is hurtful, but doesn’t care that it hurts people.