You would not have a lot of trouble with your kid trying to be best in basketball, or football, and make a name for it.
I don't think the same would apply to OF or porn. Totally different things.
I mean, this is purely for socially constructed morality reasons.
In actuality, both require you to sell your body, and both can have long standing health effects. If anything, I would say the typical OF model sells their body much less than an athlete. I mean, I don't think they're going to tear their ACL.
And also, both offer no real tangible value to humanity. Sports do not produce anything, neither does porn, they're purely for entertainment. A cashier at McDonalds is providing more absolute value to the world than even the most esteemed athlete.
That's not to say that athletes are bad, entertainment and games are important. But you can't just say one form of mindless entertainment is more valuable than another form.
You do aware of being best in sport and what I just said are hella two different things right? I wish my kids aware that *hell is other people*. Otherwise being a porn star or being a sport star makes not so much difference. Both can give you mental struggles and physical injuries. I think the another comment articulate it well too.
Edit: And sure It's concerning that the society being shallow but OF and porn are just consequences not the cause. Without them we would have something else to turn important human experience(ie sex) into a commercial show and twisted it. Turn humans into tradable goods. Body commodification is just moral decay and the end of civilization! I think we already have such a thing called ... sports? Edit: professional sports