This is just something I've noticed in a few environments. I work in a nursing home right now but I think it also applies to staff who work with people with DDs*. The idea is that if a "client" or other euphemism is rude to you, you can be rude back to them.
Sarah: I don't like you!
Aide: Well, I don't like you either. (turning to other person) Look how obnoxious Sarah is!
Okay, let's take a minute because this is really weird! First of all, the experience of having someone who openly dislikes you come into the place where you live and take care of your personal care stuff has got to be depressing. I can't help but think it just might make someone LESS LIKABLE. It also sounds scary, no matter how principled the aide is about not letting their opinions affect their work.
My personal feelings aside though, this just has nothing in common with how service people act in, like, every other type of job. If you were cashiering and a guy was yelling at you for ringing things up slowly, you would apologize. If you were cutting someone's hair and they started bitching, you would go along with it. It doesn't matter that they're being rude, YOU WORK FOR THEM.
I guess some people would say this is because unlike long-term euphemisms, this kind of customer can take their money away from you at any time. But I don't really think this is the whole thing. Bus drivers are pretty nice and I'm not exactly going to go buy a car if they piss me off. When I worked at my college dining hall I would have gotten in trouble if I'd been rude to someone who was eating there, but they were going to eat there anyway.
Really I think the whole business is more simple. When you are being paid to do things for other people, you put yourself out, because you are working. If you did whatever you felt like it wouldn't be a job. It would be doing something nice for someone because you wanted to.
Probably a lot of people in service jobs like doing nice things for people, and that's part of the reason they chose the job they did. But I think some people who do support work never really separate doing their job from doing something for someone else in real life. They don't do bad work--they really care, and they have good relationships with the long-term euphemisms who meet them halfway. But if someone doesn't meet them halfway, no professional code snaps into place, no "the customer is always right"--there is just this person you have to take care of, just like if you had to take care of your grandma and she was mean. But it's not the same thing! You work for them!
I just think this is creepy because I would be creeped out if I was the long-term euphemism everyone hated and kind of glared at while putting my clothes on and giving me a shower. But it's also just not professional. Sometimes I think it happens because, without really acknowledging it, we recognize that this class of clients can do less to punish us if we piss them off. I don't think this is as consciously selfish as I'm making it sound, but that's one of the things that makes it scary.
*(Actually I think there's an extra thing when it comes to DDs, because staff sometimes have a feeling even if they're working with an adult they are supposed to be shaping/improving the person's behavior in the way they would with a kid. So it's not even that they're being rude in response to rudeness, it's that they actually think doing their job well includes telling a person to say please or think about how the things they ask for affect their staff person.)