Learn not to be a jerk. This isn’t an essay.
You get a B- in civility.
“You get a B- in civility.”
Rather than just politely accepting the constructive criticism, you lash out - so you get a “C” in civility.
I think it’s important to use grammar correctly. I believe that people would always prefer to do any endeavor correctly, no matter what the activity. If you think it is uncivilized to correct misused English, that’s fine.