The number one mistake I see people make in their life is giving importance to how other people treat them. How another person acts towards you only says something about that individual. It doesn't say anything about you and it doesn't say anything about any "class" or other group of people.
I've been treated as shit thousands of times in my life, for no reason, and treated well ten times more, also for no reason. We get these things in our heads that it's about us and that we're the victims of a world of discrimination, but what it was in reality is that we met some rude people and some jerks.
To get your foot into the door at all, as you mentioned, you have to demonstrate some value. Is that an act? I wouldn't say it is. I would even say that many people will have more patience and be more open to you if you're from a different background than them, or if you're young. The demands to be considered a part of polite society are usually low, so that anybody who wants to participate can enter. Politeness is first, which is free to learn and free to execute. Apart from that you need clean clothes and a clean person. Does that mean other people have to like you? No. If you're from a rough background and move into a different rough neighborhood, the people there will not necessarily like you either.