From the article:

"It wasn't the right thing to say, obviously," Henderson said on Tuesday. "It wasn't what I wanted to say. It was more of a joke that I was trying to intend. I do have a good sense of humor, and that probably didn't come out quite as funny as it should have."

Henderson said he didn't, in fact, know Bisping was knocked out cold. (In a post-event press conference, UFC president Dana White said that Henderson told him the same thing and had apologized for his comments.)

"It wasn't intentional," Henderson said. "I didn't know he was completely knocked out or done until after that second punch, and that's exactly when I stopped. And I've hit guys just as hard almost right on the button like that (first shot), and they fall down, and the fight continues because maybe I didn't land the second shot right or the ref feels like that [my opponent] is still able to defend himself and he squeaks past and holds on. But I didn't want that to happen. That's why I was on him so quick with the second punch."

During a 12-year career spent mostly with the UFC and PRIDE, Henderson said he's learned to finish opponents once they're in a vulnerable state. Besides, he said, in that split second between the time the first punch landed and he reared up for the second, he didn't have to assess Bisping's state.