Why do you care if i call you bro... jesus Christ bro
The simplified answer:
Being called a somewhat familiar term by everyone except my family and the 10 people I call friends (though 6 just because of the shared interest that brings us together on a regular basis) feels to me like someone is punching me from the inside.
The answer with context:
As I mentioned in my other comment, there are few I detest more than myself and I hate our species. Among other things, this has to do with the way I view myself, and a fake friend I didn't recognize as such until it was too late.
Yes, that's a problem, but therapy (and my actual friends from before) got me to where I am now, which was enough to end my suicidal thoughts because I am what I am (physically and mentally).
What it hasn't helped with is that anything that even remotely reminds me of fraternizing with people I don't know triggers this problem I have.
It's not something you could have known, and it's something I really don't like to talk about, but that's why I have a problem with being called "bro."