Its not a comparison, prostitution literally is physical labor...
> is no different from comparing selling your organs to prostitution
...whereas selling organs is not prostitution and vice versa.
> Indeed, giving away for free a part of what you earned is bad, but giving a part of yourself, be it psychological or physical health(which should not be separated, actually, but lets not complicate things. Lots of things we can lose and still continue to live), is worse.
Much wage labor, both physical and otherwise, involves sacrifice of psychological and/or physical health. We have, in fact, a massive labor regulatory and enforcement bureaucracy that exists not to prevent that, but to try to limit it to what is deemed reasonable for each specific job. (Including, where it is legal, for prostitution.)