"I did mean the part about having trouble with girls. It is true that I have fallen in love with people in the lab, and that people in the lab have fallen in love with me, and it's very disruptive to the science. It's terribly important that, in the lab, people are on a level playing field. And I found these emotional entanglements made life very difficult. I mean, I'm really, really sorry that I caused any offence – that's awful. I certainly didn't mean – I just meant to be honest, actually." [1]
He was given a chance to clarify, he doubled down. While I'm not saying a joke should cause people to be fired, but this is clearly more than a joke.