Well, an assumed connection between legality and morality is perhaps part of the disconnect.

Having sex with 16 and 17 year olds is not morally wrong *simply because they are legally considered minors and you an adult.

Having sex with 16 and 17 year olds is considered morally wrong, by some, because the state of their mental maturity is often far below that of an adult even 5 years older. Consider the biological “growth” of the human brain; having not fully developed, their behavioral maturity follows suit. This means their ability to reason, their ability to act in their own best interest, is less than your own. At a certain level of disparity, this imbalance is usually considered “taking advantage” of someone. Asking them to do things they have less an ability to understand than yourself starts to look a lot like coercion.

*ETA

But 18 and 19 year olds are not kids you idiot they are both legally considered an adult in most parts of the world

But you’re still ignoring the huge difference in power dynamic. Unless you want that, in which case I can’t see how you could call that moral.

Obviously I would never have sex with 16 and 17 year old woman because they both considered minors which makes it morally wrong for me to have sex with them because I’m an adult.

Since you still struggle with the morality of the sexual power dynamics of having sexual relationships with those too young to understand the concept, it’s clear that it’s not any sense of morality stopping you— it’s the legality.

I have no doubt you’d fuck kids if you didn’t fear the legal consequences.

So the question remains: why do you wanna fuck kids so bad, and why do you think fucking kids is moral?