The only parts of "freedom of speech" not allowed here are swearing(cause of younger kids), porno(same reason), and arguing, though why arguing is generally deleted, I don't understand. It's like forcing everyone to either agree, or shut up, IMHO. The "no forum advertising EVER" thing, I don't understand either. Most likely, I don't get it because it's not my place to know these things. But beyond that, PC has, for the most part, the same level of freedom of speech you'd get anywhere else. Indeed, even in the US, you can't just say whatever you want. No reason it should be different here.
BTW I know you are obviously taking a cue from Gamer2020, but he's being too overdramatic about his own rulebreakings. There is only 1 thing worrying me out of all the links in his sig: the thing that says "You have no rights on the internet". That statement is troubling.