Yes, because it's the way the human mind works. I work with it to avoid dehumanising categorisations.
Your brain will do it on its own. But its up to you whether you accept the conclusion or not.
We all do I'm afraid. It's a coping mechanism encoded into our psyche. The human mind attempts to access risk. This goes back to the days before civilization. Different needed to be accessed for survival. Lions, tigers and bears oh my! It's simply easier to pigeon hole different. Young black male at night, oh my. That old white granny could be packing heat and ready to blow your brains out, but that's not where she's been pigeon holed in your psyche. It's not right and it's not fair but it is so and I don't care how liberal you are. If you don't know the person you're going to make assumptions about them ba<x>sed on your cultural background and what your in-groups have taught you.
Yes...everyone does subconsciously
Sizing them up perhaps. Not really judging.