They want to watch because they are emotional fighters on different ends of the spectrum.
Jones is widely hated now. But still has many fans.
Chael is widely hated. But has always had many fans.
Chael has no chance. But people love or hate both these guys. Love and hate drive PPV buys. A lot of fans are usually all the way on 1 side the other with these guys. The TUF ratings will be up. PPV will do well.
If they didn't have the TUF show anymore this fight wouldn't of happened. TUF is a cancer to hardcore fans. The last TUF I watched most every episode was Nog/Mir. But I will watch some of this one because of the entertainment. And I have never been a Sonnen fan. But I've warmed up to him, especially if he is talking crap to Bones. What has ruined it a bit for me is knowing that Jones has little problems with Chael now. Back when Chael was trying to step in it seemed like he genuinely didn't like him. It will be fake bad blood...but 95% of bad blood in the UFC these days is fake. That is why I am a Diaz fan. They would never have to or agree to act out fake beef for ratings.