I think you're both right.

It'd be nice if we could live as you suggest.

But the fact is that people are not just who they are, but they're also partly what they were forged to be by society. If natural selection really is a blind watchmaker, then society is the village idiot when it comes to "forming" individuals.

I believe the result is that some people only think they want certain things because they've essentially been brainwashed since childhood to believe those things are good and desirable. In this way, then, I have to worry that "age gap relationships" really are a problem.

Is anyone really capable of making their own choice? Even if you accept "free will" (I don't), the number of un- and sub-conscious influences we're exposed to - especially as children - can really do a number on us.

I have no way to tell a good age gap relationship from a bad one. I don't know that anyone does. So perhaps something like Jgln's approach - of raising awareness of just how bad it can be - is the only reasonable way forward.