I look at it like this: if you've accumulated that much money AND have had time to use it to help others, and haven't? Glub glub time.
If you've suddenly stumbled into ludicrous wealth because a psychotic demigod drowned one of your forebears? Well, it'll take at least 48 hours for you to put that money to more philanthropic use. I figure we can give those folks at least that much of a grace period to decide to be better.
The next Superman can handle them if that's not enough to change their attitude.
And realistically, this would create so many power vacuums all at once that civilization would probably collapse overnight, but you can only get so realistic with superpower hypotheticals.
Not sure where you're pulling that from. Neither the original post nor my response said anything about legality. OP said these assassinations were the "logical sequel" to the CEO attack, without any evidence the two are directly related at all.