I saw the post he was commenting on and it is not in the same context as what you are saying.
“sneeze and Ill blow your s#$% away” is what the supposed cop stated. That sounds like someone who shouldn’t have a gun let alone a badge.
The loon in this case didn’t decline any commands so use of deadly force would be murder.
If a suspect is holding a weapon and does not comply with commands, (IE: does anything other than what they are told) then deadly force would be permissible and expected. It wouldn't matter if the suspect were legally armed or not.