Also keep in mind that you can choose not to post Emilie's nudes on AlwaysFan, in which case she becomes a non-nude model and is still able to do well on the site, which I think is worth mentioning here. That was what I did for my play through (love/romantic/harem route), and I have to say it was one of the sweetest stories I could ever experience in these AVNs.
As for the other models, as already mentioned by a number of other posters, some choose to pose nude even after you tell them to only do what they are comfortable with. So, combined with the overall worldview of the game where the employment rates are just absolute crap (this is mentioned a number of times in the game), which pretty much robs the main characters' options to explore other lines of jobs, you can make sure that the MC remains sweet and noble through which decisions you make. It's just that the premise of the game wouldn't work if the girls didn't become models on AlwaysFan. After all, the very title of the game is "AlwaysFan" to begin with, lol.
Plus there's the silver lining of Emilie's self-confidence growing as the result of her modelling for the site, and also having a supportive community (I know a thing or two about supportive communities as I've been a moderator for a wholesome camgirl for a few years). I don't know what happens in other routes, but at least for the love/romantic route, you can make sure the MC remains respectful. Sure, there's that "Megan incident" but even then, you can choose to keep it a one-time thing and also not cum inside her. Or maybe you can choose not to help her that way altogether, and still be able to help her and Nicolas get back together? I found Megan pretty (small boobs are my thing) so I caved and went along with her plan, but still couldn't bring myself to unlock the "Sorry Bro" achievement, and also got to see the two lovebirds get married in the end. It's better for my conscience that way, I mean, the dude is my best friend, lol.