Why are humans like this?

I saw a comment om social media today that made me quite mad. The comment stated “Fit people don't judge.” This comment was posted by – a very fit person – on a status from a not so fit person expressing their feelings about the way they were treated in a sportswear shop. They simply went in wanting to buy some sportswear, and recieved no service, instead the staff made remarks and laughed and talked as a group. He left the store. This is a status which I can agree with – the staff in sportwear shops are quite often extremely rude, or give no service at all if you don't look like you goto the gym every second day. Maybe not ALL fit people judge, but lots do. Lets be honest, EVERY single person on this earth at some point, has judge another human. And, very honestly, this is the exact reason why I still pay a membership for a gym that I never goto. I would go, and I would be judged. I cant even go in there to cancel my membership. I didn't know how to use alot of the equipment, nor would anyone help me to use them, just laugh from the otherside of the room. I would hear comments from others like “shes skinny, why is she at the gym?” or “Probably trying to get a booty” , being laughed at because I couldn't lift much weight, not to mention, and while lots of you will jump up and down about this remark, but guys looking at my ass as I walked around the gym. (Just FYI, there is a very clear difference between looking, and checking out, and us females KNOW when we are being looked at like a piece of meat by males. Its nearly instinctual.) I felt alot of pressure from staff and people in general to “get bigger”, which was not my intention or reason for going to the gym. Now this doesnt always happen, I get that. BUT, for me, no I obviously wasn't trying to lose weight, I just wanted to get to a point where I felt good about myself, and get back the strength my body once had, inside and out. I have weak lungs, and as time goes on my muscles throughout my body are growing more and more weak. I didn't want a transformation, just to feel good and strong. To feel happy and normal. However, instead of feeling good and confident, these snarky remarks and comments made me feel worse. Like I wasn't allowed to be in a gym, because I didn't look like them, or aspire to. Or because I wouldn't train as hard. So point being.. Some fit people do judge.. everyone does. Can we just STOP being assholes to each other, and learn and accept that people live different lives, have different lifestyles, different aspirations and different opinions, fuck we are all individual people and this includes our bodies, why can't we just accept each other for who we are?