North Korea hacked him, so he took down its internet
You can admire his spirit, but not his judgement or actions.Attacking a foreign power, or serving a foreign power's military, are both crimes from what I know (am not a lawyer, but cybersecurity tangential).Specifically, taking out the power affects everyone who lost power, and could be construed as an attack that causes harm to foreign officials. As a result I'd think https://www.law.cornell.edu/uscode/text/18/112 applies. Again, not a lawyer, but the days of hacktivist actions without major retributions have been gone since the early 90s (hackers often get worse sentences than rapists or murderers). It's a different world now, more's the pity. For some background I recommend The Hacker Crackdown (https://www.mit.edu/hacker/hacker.html)