It's true of a lot of the non-Marxist Left, too.
> The environment it creates is ruthlessly competitive. Winners win big, losers starve.
Im struggling to see how you imagine a crackdown on voluntary sex work would make that better, except as a way of draining more resources from everyone (itself making more people starve) to guarantee that fewer people could make a living in voluntary exchange (making even more people starve.)
Sure, I think with genuinely left policies, there's be less people who felt that sex work that lots of people not doing it find unacceptably degrading was a net win, and so fewer people choosing to voluntarily engage in that; capitalism naturally is economically coercive that way. But there's nothing particular about sex work here, fewer people would accept agricultural field work at current wages, absent economic coercion, too. The fix for the problems capitalism creates index work has everything to do with capitalism and very little to do with sex work.