People have all sorts of means of justifying their actions.
Even psychotic serial killers have explanations that appear rational to themselves.
However the fact remains, we live in an advanced global mostly free-market civilization, and as such, prosperity does not need to come at the expense of another.
While there are disadvantaged groups, on the whole everyones standard of living is increasing around the world, and that is why we live in the greatest time of mankind.
Psychopaths should be banished, whether they wield a knife or a keyboard.