There’s a thin lining between being yourself around people and showing manners/respecting another person’s feelings. There’s a certain way of saying something and behaving when you come in contact with someone else whose views, notions and ideas may differ from yours. You can be yourself and still not be a complete asshole about it. You can get what you have to say across to a million others in a manner that won’t hurt anyone’s sentiments. Yea, I know, there are probably a few people who don’t and won’t want to understand what you’re trying to say and are ready just to start a fight, but that reflects on how their morals, understanding levels and manners are.
The way you talk and behave among and with others depend a lot on your values, morals and mannerisms. You could always conduct and carry yourself in a way where you aren’t putting someone else down. Yes, not everyone is going to agree with you, you might even hit a nerve with some people.
I know a few who'll say we're allowed to say whatever we want and think and that people are going to judge anyways, true, you're free to speak up and get your thoughts all out in the open, at least you'll have the satisfaction of not being a jerk about it (unless that's what you want to be, then you can ignore this whole post, sorry if you've read this much). I'm not saying you have to use super refined words or talk all sophisticated and elegant-ish but you can be just nice. Pride and ego will probably get you somewhere, trust me though, that place ain’t going to be any nice.