I think Bisping was just super pissed off. I don't agree with the knee, yeah it's blatantly illegal but maybe he was trying to time it but saw red and just went for it.
Lets not forget all the terrible cringy videos Rivera made leading up the fight, the suggestion that Bispings Australian wife has the clap plus all the phonecalls and shit Riveras team spewed on Bisping & family at the hotel. As I said I totally agree with the knee being illigal, BUT I was pretty happy to see Bisping telling Rivera to fuck off when he stumbled over to him all roughed up with a little sad face and outstretched hand.
Also Bisping didn't spit on anyone, he spat in their corner on the mat, big difference.
Always supporting Nick Denis in his quest to educate and defend humanity against the zombie apocalypse.