Judgement is an animal instinct as you say, but I think it can also be a cognitive habit.
Our self awareness - in theory - allows us to change our habits, or at least temper them.
So my experience of this is that my default animal instinct is to automatically judge people in a negatively biased way (which I think may come from our evolutionary instinct to try to predict danger - or if not, perhaps something encoded in me specifically at an early age) but I have tried to adopt the conscious habit of overriding this initial instinct with “mediating thoughts” like “what do I really know about this person?” and “how would I behave if I were in their position”.
I also try to simply remember my discovered self-knowledge that my instinctive emotional response - pre-thought - is to be distrustful or overly negative. Just keeping that in mind helps automatically attack the judgemental thoughts as they come up. I guess it helps me recognise the pattern and not trust those thoughts.
I’m quite convinced that I’ve done this for long enough now that my “habit” of automatically judging people has lessened over time.
The instinct is still there, but better cognitive habits have been overlaid on top.
That said, I still feel I’m about 5-10% along in terms of progress compared to where I’d want to be! (And in reality there is no “end” to this work).
My outward behaviour towards others is generally “good” - I think - but I find myself often frustrated at the instinctive negativity in my head which I have to proactively counter - each and every time.
And because I’m human, I sometimes (ok… often) forget to.