Indeed

So where do you draw the line? What if a 19 year old dates a mature 14-15 year old? Is that OK in your book, assuming theres jo significant power difference (if you agree its ok, explain your system of measuring 'power difference')?

Just because the specific number 18 is a social construct doesnt mean it should be a free for all. We do live in a society after all, and need to draw the line somewhere. Also, because in most countries (sans the US where you can drive at 16, go to war at 18, but only drink at 21) there is a definite line between adult and non-adult(the specific day you turn 18). This is necessary, even if it is a bit ridiculous that im not allowed to do certan things 24 hours before my 18th birthday.

In my country, and most if im not mistaken, if 2 underage people are dating, no one expects them to "pause" their relationship as soon as the older of the 2 crosses the threshold of adulthood, until the younger also crosses it. But if an adult starts a relationship with someone underage, thats not OK, abd you beed to have a cincrete definition of what 'underage' is, abd when exactly that is.

And that stops the non-morons from using the guns to end the morons rule how?

As a technology, crypto does (on paper) solve most problems with FIAT currencies. The problem is as always the people using it. Just like the article linked above, when you have mono/duopolies it can become a problem. In terms of crypto, when people treat(ed) it as regular currency and kept it stored in centralised locations, it makes it easy to take advantage of them.

Likewise, literacy about a technology starts off low. Just how in the early days of eshopping using a visa/mastercard there were probably many people getting scammed to input their card details in sites they shouldn't have, there are many people who dont know how to be safe while using crypto today.

Instead of being bitter to the tech because you or people you know got scammed by being careless with their money, see the positives of the tech and make steps to educate them so it doesnt happen again.