I wonder why certain individuals derive pleasure in bringing you down or demeaning you, especially when we know that nobody is perfect.

I'd have to get context if you're referring to something personal but I would say just off hand, all things in society come from a subconscious and conscious place. There are people who want people to fail because they feel bad about themselves, this translates into everything even by the way they vote, how they conduct their relationships, culture everything. If you don't value yourself, you don't value anything else either so naturally they'll want to bring you down to their level. They try as hard as they can to get you to act badly because that's how they feel about themselves.

People who can't control themselves very well, will try to control you. I kind of remember that when I know that there's a specific situation where I know I'm in the right. I'm not right 100% of the time but there's been a few situations where you just know you're in the right and they want to grind you down until you're nothing.