You lost your temper which you admitted, and while under gunpoint you decided to start babbling "YOU'RE SPAWN CAMPING! YOU'RE SPAWN CAMPING!" while swinging punches at the one aiming a gun at you.
While there was indiscriminate shooting, you retaliated in the worst way on somebody who was actually trying to roleplay with you. Running away or wailing on your attacker is never a good idea, and shows clear disregard for your life.
Another UA member will review your appeal and decide on the outcome.