... well... We here in the USA are "used" to having what we call 1st Amendment rights: Free Speech.
But it doesn't really apply to websites, does it?
To me, it's like seeing someone writing a book, and that makes me want to say things too. I have every right to write my own book, but no right to put my thoughts in the other person's book.

If the author of the (website) book allows me, I may add to it as allowed by the author, but otherwise, I have to write my own book.
So I liken PC to be like DocJohn's "book" into which he allows me to write some things.
edit for grammar correction