What's your point here? That all morality exists on a scale, therefore morality does not apply? That there's always somebody even less ethical, so it doesn't matter? I don't get where you're going with this bizarre line of reasoning. Is it OK if I steal your wallet because somebody once robbed a bank?
There are no objective lines, obviously. Other than those defined by law. And you know that, so asking for them is kinda disingenuous.
Everybody does whatever (legal) things they want, and everybody else is entitled to have an opinion on the ethics of those actions. But, again, I feel sure you know that. So I remain mystified as to where you're going with this?