Personally I think that painting it as particularly "men who flock to defend the industry" strikes me as- incorrect from my experience, when it comes to leftist spaces (then again I generally also stick to LGBT spaces myself).
Historically, sex work is one of those "industries" that is easily accessible (not that that is or isn't a good thing, but it is filling a need- and no, not a sexual one- continue reading but basically an employment/income need) for those communities historically disenfranchised and stigmatized; women (and some men, and- saddeningly and with no justification whatsoever for those who take advantage, moreso than in other cases- children) coming from bad circumstances, POC, those with disabilities or from persecuted communities, the homeless, and of course the LGBT community in particular- sex work is especially visible wherever the lumpenproletariat is, wherever those who are most stomped on and looked down on are, sex work is most prevalent.
As someone who has been homeless- and who is a POC, trans woman, and LGBT+ (haven't done sex work before myself, but TBH in the future the honest truth is that- I probably should, simply as a basic assessment of my circumstances I should) this portrayal is completely at odds with what I've seen, from people I've met in-person (not purchasing sex work either, I have never and will never do that- but meeting people in-person from broader community support (non-sex-work related) events, having friends who have done sex work- men included, etc).
Personally, I saw Kollontai quoted here, have read her take on the subject before, and more or less agree (with caveats). But the fact of the matter is that-
(A) Sex work exists, and will exist until the motivators/circumstances driving people into sex work cease to exist. That's a fact, and will continue to be one likely well into socialism until humanity has truly developed to such an extent that perhaps could be described as "post-scarcity." It is literally the "oldest occupation," one that has existed long before capitalism and which has its own counterparts (of sorts) within much of the animal kingdom.
(B) While legitimizing sex work (actual sex work, I'd say that expression through art is a completely different subject though also not without its own complications, and that in regards to videos/film then it gets into the profit motive and consent/etc being a serious issue) may be "icky"- improving the conditions for sex workers is something that we should support, so long as it actually improves the conditions for said workers (and debates over whether it is "work" or not, or talking about how bad it is and how no one should have to do it- which is par for the course in capitalism though I agree sex work, or rather the sex industry (not the workers of course) anyways, is a particularly unique kind of evil- will not change the fact that those under the industry are human beings with the same needs as anyone else and we should be aiding them in acquiring those first- and seriously, until we can say that their needs are covered, pontificating without offering a tangible and immediate alternative is ineffective and in fact counter-productive)
Basically- ideals are nice and all. And sex work is icky, sure, I agree (or the sex "industry" is icky, anyways, the workers or "workers" aren't). But without an alternative on the table, an alternative we can immediately offer (ie. something that isn't exactly possible without establishing a dictatorship of the proletariat) the best we can do is minimize the harm, aid those who wish to escape this particularly wretched kind of exploitation, and aid the many who- after judging their material conditions (and doing so better than we can for them- as they have their own life, their own priorities, they know the intricacies of their circumstances best, etc) decide they still "want" or rather need to engage in the work- to aid them to have better outcomes, to have better circumstances even if it is within that "industry."