1st question. Where did you get your BJJ blu ebelt. Your understanding of BJJ seems...off.    Agreeing with the points in the above post. For example Forearm crush is an extremely low percentage move.    Position over submission. Dirty fighting works both ways. The BJJ guy will be able to get to the better position to more effectively apply dirty moves.    Very few people train dirty fighting (ball strikes, biting, gougining) and those who do can't train it 100%. So Dirty Fighting is a tactic that doesn't take much skill or training to execute.    This all points back to the fact that the BJJ guy with positional experience can always fight dirty better than the pure dirty fighter