Or we can agree that any adult boinking a kid is illegal because kids should have the time to enjoy being kids in a civilized world.

I agree with this sentiment, but you make this sound more simple than it really is. I'll give you a true story example. When I was 17 I had a girlfriend who was 17, we had sex, it wasn't illegal. Then I turned 18 first, and it was illegal, then she turned 18 and it wasn't anymore, this is ridiculous. A teacher that has sex with an 18 year old high-school senior wouldn't be against the law either, but I think this is more problematic than an 18 year old student bonking a 17 year old student which is against the law. Its the social standing disparity that creates the perception of exploitation in these situations, rather then the violation of some arbitrary age. Teenagers are very much sexually mature in the biological sense, they are bursting with reproductive hormones, and pretending they are children in this sense is delusional biology denial

Americans can't even agree on what an adult is. 16 to drive a car and risk others lives, 18 to be armed and sent to war, but 21 to have a beer. The pure arbitrariness of this categorization prevents me from agreeing with your statement about minors and adults - I don't think anyone has a clear and consistent definition of 'adult', I mean we know what one is, but I challenge you to draw you a very precise boundary between the two in way that isn't absurd. I don't want anyone being exploited, sexually or otherwise, but I really don't think the current way of conceiving of adulthood is the best way to prevent exploitation