wow, that's a complex question, LostRed, lots of answers to that, dont want to throw any old one at you cause its quite a serious question, and different with different people too.
maybe other people are more closed-minded and judgemental than you,
maybe they have their own issues that make them feel like you are judging them when you are not, so they judge you as judging them (sometimes i feel like people are judging me, maybe they're not),
maybe sometimes you feel like they are judging you when they are not always, same as i do,
maybe they have issues about topics you don't have issues with, and are more likely to interpret them in terms of judgement?
when there is a chance it isn't deliberate, its a good idea to tell people if you feel unfairly judged, maybe they will learn something.
...what is the worst colour for toenail polish ? lol