@VibrantFox already said all the important stuff so I'll leave you with this:
I specifically said that whether offensive or not, it's bad writing. (The caveat of satire is incidental here, because that requires knowing the subject far beyond the stereotype, which is not the case of most of your examples).
You're offended I called your writing lazy (which it is), and then proved my point by lazily stereotyping me as a liberal because I said your writing was bad, flattening what I actually said. If you don't look past stereotypes, you don't see people, you cannot empathise with them, cannot understand them, and therefore cannot write them. No matter what your opinion on "political correctness", you should not want to be writing from stereotypes because they hinder you.
This is a core issue at the centre of your work. You're being more vulnerable than I think you realise. Anyone can see you're very lonely and you don't like when people point it out and how, despite your age, you're still very inexperienced with healthy human relationships, and it shows in your work. I am genuinely sorry that your experience of the world has made you put up such inflexible, transparent and brittle walls, but we are not the people who did this to you.
This is a forum for artistic advice, and mine to you is to allow yourself to listen to people you disagree with without immediately dismissing them. Your art will mature, and who knows you might even make friends who feel better after talking to you.
