"My answer is "no" because the shooter was not a current threat at the time."
100% INCORRECT.
He remained armed, he remained mobile, he remained an active thread.
Just because there was a police perimeter around him does not mean the threat was neutralized.
He gave no indication of being willing to surrender, and gave every indication of wanting to continue to kill as many people as possible.
Am I a fan of the "militarization" of police? No.
But I'm even less of a fan of allowing this guy the possibility of killing even more people.
" I've only heard that the suspect was barricaded/cornered and was talking with police for at least one hour. "
He was talking with police for over an hour. But have you actually seen how the discussion went?
You think it was "well, I'm hurt, so I'm thinking about surrendering, please don't hurt me..."
No, it wasn't.
It was an hours-long litany of taunts, threats, promises to try to kill anyone who tried to approach him. When someone has just shot multiple people, you tend to take him at his word.
"Negotiations," if you can even call them that, had broken down by the time the police sent in the bomb-armed robot.
Oh, and if the guy was no longer an active threat because he was cornered and surrounded, I'm guessing the police were to have discounted the roughly 30+ rounds he fired at them (by the counts I've heard) AFTER he was cornered?
Seems like a man willing to surrender and lacking any threatening capability to me.