This is true. Having a gun and believing it will save you from any and all harm is a magical belief. Especially out on the street. We don't know exactly what transpired nor do the police as was stated in the article. They suspect one or two men. Their faces were hidden. No eye witnesses apparently.
The situation smells of a hit. He was not some common ordinary citizen and the attackers tried to hide their identity. He was shot multiple times. I would see that as a hit job until proven otherwise.
There will always be situations that being armed won't stop you from getting killed. That still doesn't prove that banning assault weapons and limiting ammo magazines is something that must be done at all costs.