not to side with 'the man' but he never said emu's were illegal, he said they're "potentially illegal".
he also mentioned it could be a risk for nintendo to hire someone associated with emulation.
he's not completely wrong with the idea; as someone associated with emus might leak secret info in order to help the emulation community.
the sad truth about being associated with emulation or being an emu author is that if you want a game-dev job, you probably have to hide that information; if not you might get responses like the above email.
so not only do you not get paid for working on emus, it also can make it harder to find jobs.
of course, you can always be lucky and your bosses won't care.