but principle is a luxury of the wealthy

This is the opposite of true. When you're poor you can't afford to take a chance on people, so you have to rely on people whose principles guide them to doing things that help you. So when someone with these principles is suffering, it's in your self interest to help them out so they can help you when you're in trouble.

Poor communities run on principles. Hospitality, loving your neighbor, forgiving your enemies, treating others as you treat yourself, trusting each other with your life, utterly ostracizing those that break the principles, etc.

This is also why religion is so big in many poor communities. It's a set of principles for that community to rely on that is predictable even if it isn't perfect. You don't know which principles will only have you to work for others and which ones will have others work for you, but in total you will all work for each other when you most need it, and that helps you through the worst of poverty.

And principles work. They're massively profitable for every society that has them. Socialist healthcare is the principle that we all pay for everyone's health care no matter what, and it extends people's lives by 5 years while costing 70% less compared to capitalist healthcare.

Between people who have fewer principles, trust is expensive or even impossible. Every piece of nuance opens up risk that you have to mitigate with labor or reserves.

Principles are so massively beneficial that we are immediately suspicious when someone with both power and principles doesn't make our lives better. Are we really in that unlucky small percentage of people that pay more into it than we get out, or do their principles not care about us as much as we thought?

The DNC has principles, but caring about the working class is pretty far down the list. Mamdani ran on principles that put the working class much higher, so he could be honest about the policies that result from them and just win.

Trump ran on fostering that suspicion into complete disbelief. The DNC won't help you, nor will establishment republicans, nor even religion and its commandments ("Love thy neighbor"? No, "the sin of empathy").

When nothing means anything and you can't trust anyone, how can you keep yourself relatively safe? Well, you try to be the most like the most powerful people that will accept you (for now) and bundle together with those that are most like them to fight those who are less like them.

And because you can't trust anything, the best way to determine who is like them is things that are relatively visible that can not be changed or are difficult to change - race, religious rituals and paraphenalia, culture, nationality, wealth and power, cultish devotion to the great leader, etc.

This is fascism, and there is no exit clause. They'll fight until they lose, and if they ever run out of enemies they shrink the circle and fight everyone outside that.

So let's honor our principles. And if we find that our principles keep hurting those around us, just get better principles.