You may be a bit confused on the actual rule. The trapping the ankle to the buttock for 5 seconds rule is only in effect if the bottom wrestler is broken down on the mat. In your video the top wrestler was off to the side attempting to break down the bottom wrestler. The rule you are trying to refer to does not apply in this situation.
If the coach went to the table to argue that the official did not apply the rule properly, he was wrong and was penalized appropriately.