When I care deeply for the other person, it's maybe different. For the rest of the world, they unfortunately can behave however they choose. Unless you are in a position to enforce good behavior, the more you show you care, the more difficulty they are likely to cause you. The only way to deal with them is by not caring they don't afford you dignity, and finding dignity inside you and believing you have dignity and deserve to feel it whenever you are around them.
They're unlikely to change much. They are probably doing the same thing to many, many others. I can't tell you how often I feel tortured by someone and eventually learn how deep in them the ugliness goes. If they are torturing you, they may be tortured as well, and they are almost certainly not singling you out alone.
You deal with them by respecting yourself and by trying to be around others who respect you as much as possible.