This is a typical case of Prideful-directed denial
Just because you think you were right does not mean it was insulting. You did Insult the Person, you were inferiorating his intelligence by your personal standart of understanding and ended up getting VÈRY angry at it onto the wrong people.
I have been dealing with therapy a lot lately, and one of the topics i was big on getting pissed at is being confronted head on with my mistakes. In you, with this post, i see the very same Thing. Your misguided understanding of Insult and truth have led you to being a very offensive Person and you don't even realize it because, again, you were taught no better than to believe such is the true right course of action.
However, do ask yourself, if this many neutral individuals tell you it is wrong, how can you still be so flawlessly convinced that WE ALL can go fuck ourselves because you apparently think you are all right and true and innocent?
at one or two people, maybe, i would believe you might have been falsely punished.
But at....everyone present....less likely.
Yeah it is hard to admit you are right, trust me, first hand experience. But as i said again, just because you were true with a Statement doesnt mean it is not an Insult. sure, some people arent really a bright bulb of light in the groundless canyon of stupidity, but that doesnt mean calling them out on such is justified. there are many ways to say it nicer, too.
I hope you will come to Terms with your mistake and will act up at least with a nicer choice of words.