IS CONFUSION AN EXCUSE FOR MURDER?

I feel absolutely no sympathy for Dallas policewoman Amber Guyger, despite her assertions that she killed Bo Jean because she thought he was an burglar in her apartment out to do her harm. First of all she considered him a burglar. Since when is burglary a killing offense. If she had a gun and he was unarmed, why didn't she just hold him at bay until the arrest. Since he was relaxed in his own home having ice cream, I doubt that he sent any threatening messages. She was just a over-reacting,  unobservant,  incompetent law officer, who didn't even have the skill to recognize that there was a bright red welcome mat outside what she assumed was  her door. Did she think a burglar put it there. Poor Jean, a young man enjoying the comfort and privacy of his own apartment when an addled trigger-happy cop bursts in, takes no note of the surroundings and situation and kills this innocent resident. I don't care how confused, tired and overworked Amber was. I say guilty of second degree murder.