I've been thinking about that question. I've been trained to reject that question all my life.
One of the things that used to frustrate me back when I taught sailing was the way kids would never try force as a way to solve problems. They'd try all the non-force alternatives they could think of and then give up. I'd show up and push or pull hard on the obstacle and it would be overcome. I used to say to them, "Brute force shouldn't be the first option but it should always be an option."
I'm starting to feel the same way about, "What's in it for me?" It shouldn't be the only question but it should always be a question.
Sometimes we act in a self-sacrificing way. Always?
To be sure, the contempt was for the man who "Only wanted to know what was in it for himself. But that "Only", like a lot of qualifications wasn't really qualifying anything. The message that was being sent was that it wasn't ever appropriate to ask what was in it for me.