If he injured by moving in a strange way, then the injury is his fault, learn to move properly or don't get in a position where you don't have to move that way if you don't want to get injured.
BJ is always moving in strange ways. His flexibility lets him pull off maneuvers that few others can. It was simply luck of the draw that his crazy style caught up to him in that fight.
Do you really think BJ would try something in a fight if he hadn't drilled it and developed a degree of proficiency at it? Even "lazy-BJ"-era Penn deserves a bit more cred than that.
Did Brandon Vera need to reevaluate his stand-up and "learn to move properly" after breaking his hand in the Sylvia fight?