This is just going to open a can of worms of other topics that you'll just be biased against. You'll respond with "love is not defined by ***" and then I'll respond with "Either or, As an adult, I can't date a 16 year old and say 'we're in love with each other, we aren't having ***, so it's ok'". Then you'll respond with "That's against the law and that I'm talking about two consenting adults". I respond with the fact that you don't see the hypocrisy in your statement. You'll respond that you're giving up and that it's a waste of time to argue with me. Pages later, we'll rinse and repeat.
Sorry to **** in, but if you don't do anything physical, is there a law against "dating" an under-aged person? I don't believe there is. Even kissing them could be illegal, but simply saying "We're dating and in love" isn't against the law. Arranged marriages, for example, still do happen in the US and are very common around the rest of the world. Sometimes children are promised even before birth. These people would be "dating" even if they've never met.
The consent issue, on the other hand, is a perfectly valid point. That you seem not to believe consent matters in these situations (or at least you're writing it off as hypocrisy... which honestly makes no sense... can gays not consent?), is another matter entirely.