Stereotypes exist for a reason, and those reasons are completely and utterly valid. Bold start, but think about it; If people didn't assume or judge others, how would we know to trust someone or feel secure and stress-free in everyday life? Judgments have been around since the primordial era of human existence, and that isn't bound to stop anytime soon, and here's why.
As infants, we are instantly exposed to an important decision with every blurry figure we encounter-Should I trust this being? You instantly have to judge little things about a person, like if their heartbeat and voice are soothing, if they are soft to touch, or if they are gentle and want to protect you. This is just a a psychological development theory by revolutionary psychologist Erik Erikson(Great Name, really unique), but it proves a great point. Either a baby likes you and finds comfort in being held and fed by you, or they don't. Infants judge, as nature intends them to, so why is it so bad in society now?
I'll be brutally honest here, and you need to be when you ask yourself this question too: Do people of different ethnicities and races frighten you occasionally, just by looking at them? For me, yes, sometimes. People of every race sometimes scare me in certain situations or places, but that is how we become aware of dangerous situations. Imagine you were walking home and instead of going an extra 3 blocks around some buildings, you decided to cut through an alley instead. The alley is pretty regular, and you've walked that route a few times, but this time, you look down the alley and a group of very large black men are about 40 feet away, making sexist jokes, flipping coins into their hands and stumbling around, disoriented like. Are you likely to walk down the alley and walk past those assumingly fine gentleman? Chances are, no, you're not.
In this generation of ours, if you choose to even think anything but "That's my equal" about anyone, you become a fascist, racist bigot who voted for Trump because you love guns and want to shove them in everyone's face about how great they are. Thats another stereotype, right there! Its almost always false to encounter that exact type of person simply because they voted for someone or don't think everyone is equal because of social classes. You can't say what I'm saying and get away with it very often because you earn a stereotype, which brings me back to paragraph 3 up there.
People are different, people are NOT equal, and it is almost impossible for it to be this way. Everyone being equal in the eyes of almost all others is called Communism, and it doesn't work for a reason. It's natural to categorize and stereotype people, and often you might learn you're wrong, but sometimes, you'll be right. You pick who you talk to in classes based on how they dress, look, act or talk, so what is so wrong about doing the exact same thing with everyone else? Someone had to of thought "There's a Muslim man over there, he might blow me up" and end up correct. Once again, that is not always the case, but if you want to look after yourself in every sense, you have to judge those around you, THEN learn who they actually are.