I thought Ong was hurt before that day, knew he was hurt but underestimated it and then went to train with Khali.
I mean, if it was me and I knew I was hurt, I wouldn't have gotten in the ring. They didn't "force" him into the ring. And the fact that he was training with Khali didn't help matters. You can really point a finger at everyone involved, but in my opinion, most of it has to go to Ong.