Well yes it's intent that matters, your not I hope trying to cause brain damage or rupture a spleen, you are setting out to deliberately break an arm,
The problem is with mma, contests should be stopped if it's an obvious miss match, which seems like a lot of them from the little I've seen in telly at least they should be stopped at the first sign of distress, blurred eyes loss of balance serious blood injurt , co ordination, taking undefended blows, much as they ( should ) do with boxing.
Saying an arm break is ok, because the rest of the rule set is bordering on the barbaric is faulty logic to my mind