Life Advice Request - When Gets Money Too Dirty To Take It?

When I finished school, I got into the underground casino scene as a croupier (but soon mainly worked at the poker tables). During that time, I lived in a very difficult family environment and the money suddenly meant complete independence to me. The problem though was that I was very immature and soon ended up in the hookers and drugs lifestyle (without the drugs) and pretty much just spent all the money I was earning on a lifestyle to numb my private problems. Retrospectively, I consider this time to be an absolute mess and a terrible mistake.

After a few years, I decided that I had enough and went to university. I worked on the side and graduated with very good grades. Now I am working and earning decent money. Nothing special though.

Then recently, I met one of my former employers from the casino scene whom I considered a friend back then. We had a random chat, but I was in a hurry so we exchanged numbers to maybe meet for a coffee or so. A few days later I received a call from him, asking if I wanted to work that night. Given that I still have a good amount of student debt, I said OK. The money is still great, which means roughly 100€ per hour (this night it was a bit more, i. e. just over 1k for 7 hours).

This all sounds quite good, but now comes my problem. The people are the absolute scum of society. There are a few businessmen (mainly restaurant owners), but the vast majority earns the obscene amounts of money they gamble away with human trafficking or drug dealing. And their behavior perfectly mirrors that most of them have never learned basic social etiquette or seen a school from the inside. They are mostly friendly, though it’s certainly not pleasant to work with them (however, that is somewhat always the case in working with customers who come to lose their money).

But, given the money, I'm not sure if I'm overcomplicating things. Like what is my problem? Am I so sensitive that I can't strip the situation of it's ethical weight and focus on the good things? I could work for a bit and pay off my student debt, put some money to the side and then just leave again. This could be accomplished in a year or so and otherwise would probably take me close to eight years. My current friends don’t know about my past, but they’d certainly all say that I’m a fool to not take the money. However, like in the past, I always have a constant feeling of failure and guilt around these people. Something like „I shouldn’t be here. Look at these people, how could I get so low. “. Somewhat hard to describe.

Maybe some of you guys could share their two cents on the issue. It’s basically (1) should I set a money goal, then go for it (no matter my conscience) and leave for good as soon as I hit it or (2) should I not care about the money and rather hold true to my values (not working with heartless criminals being one of them).