That's a good point, I suppose it's possible someone just recreated it as a joke. At this point I wouldn't put it past either the CEO _or_ some random internet troll.
Yeah, once you're at the point where someone can't distinguish your behavior from that of a troll, well...
At any rate, they should have done something to prevent anyone from registering with your username. Even if it's just a one off redirect on their reverse proxy/gateway.