You guys want to play the "what if" game. Who knows if he was still carrying out his duties?
The Signal chat group had no chance of being hacked-into and that they weren't going to be accidentally adding enemy combatants into it. It was a mistake that won't happen again. There exists a world where you don't need to fire people immediately.
Neither did I. He wasn't even close to my first choice. But with enlistment booming, standards being restored and his first mission a complete success, I'm less concerned than before and I have no doubt the mistakes in using the Signal app will be corrected going forward.