Signal is an approved tool, and was downloaded on his govt device.
Discussing classified information using Signal is not approved. I'm no lawyer but it probably violates the Federal Records act, as messages were set to expire on a 30 day schedule.
Yes, and if you make a "human error" that is really, really bad then you should be fired.
I mean, Jesus Christ when I was 16 and working at a Dairy Queen I saw people get fired for their drawer coming up a dollar short. Why are we holding fast food cashiers to a higher standard than our top government officials? Does that legitimately sound okay to anyone?