My arguments to justify it are the following: 1) Don't hate the player hate the game: It's not immoral to operate in the most efficient manner given within a given system. 2) The people who would pay for this product, would already otherwise pay for someone else's product, so I might as well be the one to profit from it if someone will regardless. 3) It's not illegal. 4) there's already so much content out there, that there'll be a marginal effect with whatever I distribute.
These though mostly feel like deflections from the main problem. In case anyone is interested, the opportunity is along the lines of applying 3D gaussian splatting to adult content.
You can justify nearly anything with that logic. You're the one who has to sleep with the choices you've made.
(fwiw, I disagree with both your premise that pornography is inherently a societal ill, as well as several of your justifications. But I'm not particularly interested in convincing you one way or another.)
I would suggest that you've already answered your own question. If you feel that such a thing is degenerate and leads to a moral decline in society, but you contribute to it anyway, you are a hypocrite.
Everything else you ponder reads like trying to find a way to justify away the hypocrisy, but that's not possible.
How can you care about one but not the other?
Are you ok with selling anything as long as it is "the consumers' choice" ?