Like the don't hire an asshole rule would be hire only assholes, and once in a while they'd hire someone who wasn't.
That said if you don't mind working with douches at least you'll be working with douches who aren't trying to pretend their running a 'family' as a company, which is refreshing when you're used to hearing about how the founders aren't really in it for the money but really want to 'change the world'. Financiers want to change the world too, namely, turn it into change and put that change in their pockets.
I worked on the outskirts of the finance industry, it was still pretty insane, but nothing like the guys actually in it.