Let's assume everyone behaves 99% of the time, and 1% of the time we act poorly. 
Do we just accept everything that happens in the 1% as equal? Obviously not
I'd rather be around people that might say something mean in their 1%, rather than people who might punch me in their 1%. 
It might not be who they are 99% of the time, but knowing theres a 1% chance they might get violent is enough to want to avoid them. 
Those are their true colours, because other people when pushed still won't resort to getting physical. 
I'm wondering what you did in your moment of irrational anger that got you tarred with a label you don't like? 
Bottom line is, nobody is a twat 24/7. But if we only judged people on their best moments we'd have empty prisons