"You have to be greedy to go into Wall Street banking in the first place."Not necessarily. Our society places tremendous pressure on us to be materially successful. A lot of highly ambitious people in high school, and later in college, hear that Wall Street is the best way to become materially successful. So they go to Wall Street. Once they're hooked into the Wall Street lifestyle, mainlining money, they have a hard time giving up the habit. And they're start to justify an increasingly slippery array of behaviors to maintain their fix.
No doubt there's a proportion of all incoming, freshman analysts who are there because they're greedy. It's all about money for them. Gordon Gekko is a hero, not an antagonist. Wolf of Wall Street looks like a celebration, not a cautionary tale. Etc. But I'd bet that, for every Junior Gekko, there are two or three smart, ambitious, by-the-book kids who are following the recipe their parents, their educators, and their mentors have told them to follow.
Now, let's say you're one of those kids. You land a prestigious job at a bulge-bracket firm. You're making gobs of money. That's hard to give up. Especially because you've worked so hard, for so long, to get to where you are. So you keep climbing the ladder. As you climb, you make more money. You don't want to give that up, either. Maybe you experience a few shady or ethically questionable things along the way, but hell, you're making a shitload of cash. And deep down, you suspect that there's no functional, ethical difference between you and some middle manager at a Main Street company; the only difference is that you're doing more "sophisticated" work, and you're getting paid a lot more. The lifestyle sucks, but you've been conditioned to expect that having a life is a sucker's bet. You've traded all of that for the definition of success you've come to internalize.
The failure here isn't wholly the individual's. It's also the system's. Our society, our culture, our system teach many of our best and brightest to treat money and prestige as life's scorecards.
I don't excuse shady behavior from banks or from bankers. But I don't think most bankers are morally defective human beings. I think they're Type-A kids who do what they're told. Hannah Arendt wrote about the banality of evil; I think one could write just as convincingly about the banality of greed. Or the institutionalization of greed. No doubt there are some genuine sociopaths on Wall Street, and perhaps in greater proportion than you'd find in other industries. But for every sociopath, you have some folks just chasing what society conditions them to chase.