He's not trying to reverse engineer a serial or key file.
It's being used for private use.
He's not making $$$$ at SEGA's loss.
It's not going to destroy SEGA's reputation.
and finally they are a hacker so the dopamine hit from being curious will be a big pay off.
Even if he was, then what? Quick glance at the repo does not show any kind of End-User License and even if it had what's the NSA going to do? Revoke his license? Sue him?
He's not trying to reverse engineer a serial or key file. It's being used for private use. He's not making $$$$ at SEGA's loss. It's not going to destroy SEGA's reputation.
and finally they are a hacker so the dopamine hit from being curious will be a big pay off.