I didn't read any of this thread but the title.
Who is the judge of what is "offensive" and what is "acceptable?" Congress? Vatican City? Oprah Winfrey? Bill O'reily? And with censoring comes codes, i.e "Adolf Hitler" and the number "88" (google "adolf hitler 88" w/o quotes), leading to countless probable faux paus', like an unknowing football fan proudly wearing his favorite player's jersey- NO.88- then going into a Jewish restaurant where the owner is aware of the hidden meaning and is also on edge, maybe they got robbed recently, and tells the football fan to fuck off or they'll call the police, and the football fan leaves, perplexed, deeply insulted, hungry and disappointed, because he was expecting some delicious matzah balls.
There are lots of opinions that I honestly wish didn't exist, such as the opinion that censorship is justified. But they do, and oppressing them won't make them disappear. This doesn't mean I'm toothless, I can still debate, investigate/expose, ignore, or insult what I find distasteful.
Now, if there's a forum or discussion where there's a specific, stated topic for discussion, it makes sense to discourage irrelevant topics. But irrelevant opinions aren't inherently offensive. Even still, irrelevant opinions can't really be controlled legally.
Lastly, screaming FIRE in a crowded theater isn't an opinion, it's a statement. The person shouting isn't telling anyone what to do, just informing them of an aspect of their environment. That isn't to say outright liars should be immune to punishment.
I'm guessing the OP just wanted to spark a conversation about the issue.