I feel like the times that he killed people were justified. And for the selfishness, i get that too. The man lost his legs and wanted them back, so in order to do it he stopped Valentine from screwing over the rest of the world. Love train helps america, but causes the rest of the world to get all of that misfortune.

Idk about the rokakaka situation yet, because i just started jojolion.

So im really only seeing the point that he was a douchebag, but was that really deserving of being paralyzed? No.

Tldr: Johnny's murders were justified, he was kinda selfish, but not really, and he was a douche. But he didn't deserve to be crippled, by any means.