Just because THESE kids happened to have super powers, does not make it suddenly ok for the hobo to rob children with a knife.
He deserves the death penalty for that, and in some countries would receive the death penalty. At which point, as a condemned, he was an ideal subject for a lesson.
There are countries in which rudely talking to your superior will get you in front of the firing squad, by the letter of the law. This is no argument, most civilized countries do not have death penalty at all. For the deserving part, I don't think trying to steal a bike from a kid sets one to be killed off by any margin. Threatening to get violent and harming a kid - oh, THAT may be, but he got put on his ass and left, maybe taught something. So, for me at least, at best he MAY deserve death, not is set to it. But I understand your point well, just I have much forgiving mindset.
But my point still stands about Ella, who didn't killed him for that, not even according to herself (I played this part again to refresh my memory). She killed him because he was stinking, and was the last person to negatively interact with her, indirectly but still. Not even to show the ability to transform others, she says she intended to show MC that anyway, even before he came. And when MC has a problem with that, to quote Ella "Yeah? Why do you care? It's just a fucking human."
The more I am in this debate about Ella being or not being just evil, the more I check and recollect the game, the worse she is than I originally thought.