People should be allowed to make risky investments if they want, especially if they keep that risk to a small percentage of their portfolio. Besides, the lotto and casinos exist and are still allowed in most places, which is basically what you're leaving these people to do (and what I've seen many younger people waste their money instead).

Isn't it this very website where people over and over again say that the best time to take a risk is when you're young, anyway, and don't have any responsibilities?

There's a difference between risky investments and outright scams, though, and I'm fine if the government steps in and stops the scams, although I worry that they'll start seeing every single ICO as a scam and want to stop all of them (to be fair, it almost seems like they all are right now to me as well).

That's one of the nice things about the rise of cryptocurrencies, actually, is it's allowed younger people to make bets that have wildly paid off for them, that would otherwise not been available to them. It was risky as hell for sure, but for those people that only put in what they could afford to lose, it's outperformed every other investment by many many times this past year.