Guess what, in the world outside the super-controlled environment of a school no one is going to do anything to accommodate someone else's medical issues. It's not being an asshat, it's called everyone can't watch out for every single problem every other person might have else all life would grind to a halt. Oh, that person has peanut allergies so I should get on a different subway car since I brought PBJ for my lunch. Oh, that other person is extremely sensitive to fragrances so I gotta get on yet another subway car because I wore deodorant today. Oh, this person gets migraines so the subway car fluorescent lighting needs to be turned off for the next 8 stops and make the rest of us ride in the dark. And so on.
At some point it becomes the responsibility of the person with the problem to look out for themselves as otherwise we'd require the same oppressive oversight that schoolchildren have. We're not going to set up separate "no peanuts" airplanes for you to ride. We're not going to tell coworkers what they can eat, wear, or do beyond the trivial. Life is dangerous, and teaching kids they can have the expectation that people will be mindful of their particular needs isn't the right thing to do.