I'm sorry but what he is doing is actually in no way illegal.
He's not Ddosing us, encouraging lots of players to join and to crash as server that allows public connections is not illegal. It's not a ddos either.,
He bypassed no digital locks nor did he send any unwanted packets, he just advertised a server which allows normal players to join anyway which is in no way illegal.
It is however in violation of YouTube Terms of service, so I would encourage reporting the streams although I'm doubtful of the impact.
Entering a game server when you have been forbidden to do so, could technically be considered illegal however its completely untested ground and unlikely to secure a conviction either.
Really though, the issue has been sorted with the implementation of auto whitelist.