I think there are no worst offenders here, all labor is valid as in all labor is exploitative in a capitalist system
There is no difference in work quality between painting and coal mining? Teaching children and soldering diodes? Really?
I think you can be a sex worker and keep your dignity
Again, I'm not talking about the exceptions here. Having to sell yourself for money is a horrible fate to most, to the extent that we make laws against that. You can think of this the same way.