I think what we are getting to is the semantics of it. Theoretically, it should be possible to be a billionaire without stealing and exploitation. I think that in reality though, a billion dollars is so much money that’s its hard to see how a single person can amass that much wealth without being exploitative, intentionally or not. Even if you were given that much money, holding onto it would require investing into a system that is rife with exploitation.
I’ll admit that I’m by no means an expert on billionaires and there might exist some that made their fortune without exploitation. And I’m including indirect exploitation here. Maybe that’s another point of semantics, but its one that I feel very much matters in this context.