What percentage of prostitutes across history do you believe fit into a definition that isn't characterized by exploitation?
What percentage of plumbers across history do you believe fit into a definition that isn't characterized by exploitation? Sex work is work. Period. Just like other work, it can be done because a person enjoys it, but under capitalism (or other modes of production that exploit workers) it will always involve exploitation. If you want to define prostitution as something that always involves exploitation, ok fine, but then you also have to separate that out from sex work, which absolutely does not inherently require exploitation and most certainly would still exist even if all economic coercion were eradicated (that is, under communism rather than capitalism).
Under communism (a classless, stateless, moneyless society), the economic and class relations that force people to perform sexual labor as a means of subsistence won't be present.
(Emphasis above is mine). Under communism, the economic and class relations that force people to perform any labor as a means of subsistence won't be present.
People will still have sex, but nobody will be coerced into having sex in exchange for food, shelter, or medical care.
No shit. There will still be plumbers too, but they won't be coerced into it in exchange for food, shelter, or medical care. Almost all of your arguments so far can be applied exactly the same to any number of other forms of labor.
Prostitution won't be an occupational category under communism because the purpose of labor under communism is about fulfilling social need.
So finally we get to some reasoning (flawed though it is) for why sex work would be different than any other work. You think that sex work doesn't fulfill a social need. Sexual fulfillment is a social need. There will always be people who find it difficult to find partners due to all kinds of possible scenarios (including having no time to build a relationship due to dedicating all of it to other interests or necessary labor). And there will similarly always be people willing to provide that, people who have dedicated their time to become skilled at providing that. Refusing to recognize them as fulfilling a social need is simply being sex-negative and it's always shocking to me that there are still leftists who don't understand this.