I would encourage you read the threads posted in
Rules and Guides, as well as any rules threads within other sub-forums, to answer your question. Keep in mind that these threads are not necessarily exhaustive and some sub-forums are currently without updates to their rule threads or rule threads at all, and that doesn't necessarily mean "anything goes". Staff does get the final say on anything posted.
However, if you're worried about being censored, I believe you're free to post your opinion as long as it's congruent with its respective sub-forums rules (refer to the aforementioned) and isn't violating forum etiquette (no double-posting, no spam or advertising, etc.) You also cannot post content or material that is in violation of United States law.
People are generally well-behaved and I personally haven't had to moderate much beyond banning spammers, so I don't think you have to worry too much. I will advise that the Internet Bullshit forum in particular has a greater volume of more explicit and stringent rules than most other boards, so if you plan to post there then please
adhere to them. Honestly, that's a great thread in general and much if not all of it should be heeded elsewhere on the forum as well.