Obama did a better job of hiding that he was giving military hardware to terrorists. It was still found out but it wasn't so blatantly obvious about it. Obama left a whole lot of Americans in horrific situations but not 15,000 all at once.
The point is Biden didn't learn to be this horrible from Obama, this was all on him. Just like how he did is best to screw up the troop withdrawal from Vietnam causing a similar situation in Saigon.