IMO, death is too-good for anyone who deserves to be killed. It’s an easy out.

But in answer to your question, I’m not surprised. Somebody who crosses the line in a rage is less likely to just give up without a fight. Somebody being a confrontational, hateful asshole who picks that fight and then kills someone is more likely to be like “welp I’m fucked, might as well go out shooting.” They may even believe that they’ve got some kind of moral high ground, although such a belief is more likely a justification in their own heads.