Sure, Jordon and the Wall Street guys are shitty human beings, but are they really any worse than the idiots getting taken advantage of? Maybe they're just the smarter ones. They're the ones who figured out the grift in the system.
Mr. Scorsese explains this perfectly:
"People say 'Well that type of person, that sort...' But I guess what that means is that they try to distance themselves from them; that it's someone else, it's not me. But in actuality I feel it's not someone else. It us, it's you and me. Maybe if we were born under different circumstances, maybe we would have wound up making exactly the same mistakes and choices and doing exactly the same thing."
The last scene of the film drives this point home. As mentioned before, take a look at the dimwitted losers failing miserably to try and sell that pen to Jordan. Then take a look at the audience; the rest of the pathetic masses breathlessly waiting to write down and memorize all the horseshit that Jordon has to say. They fawn over him like a Greek god when he comes on stage. This is you. This is me. We're those losers in the crowd. We're the morons that the wolves have been laughing at and feasting on the whole time. McConaughey's Mark Hanna gives the honest assessment of what they think of the normal working man: "Fuck the clients." The manager of Investor Center describes the clients as idiots. And those idiots all want to be Jordon; preying upon the weak as they work their way up the corporate ladder. Meanwhile Jordon and his boys are fucking us in the ass (well, depicting it while we're on the phone with them, at least). We want to be part of Jordon's merry band of robbers. We all want that easy "American Dream" and all the hedonistic excess that comes with it. The only difference is? We suck at it. And since we can't be like Jordon, we're going to be victims of Jordan.
People like Jordon and the rest of the Wall Street guys couldn't get away with their heartless endeavors if we weren't so susceptible to what they were selling us. Guys like Jordon couldn't exist if it wasn't for us, the idiot public that laps up everything he spews. So are the victims of Jordon's shady transactions really "victims"? Or are they just the unlucky smucks in this particular situation.
At one point in the film, Jordon screams "Stratton Oakmont is America!" This single line sums up the message of the movie. Stratton Oakmont only exists because the societal values that it reflects also exist. Stratton Oakmont is a reflection of our willingness to hurt others for our own personal benefit. It's a reflection of the unrelenting, unsustainable, never-satisfied greed that plagues this country.
So if you don't like your reflection, don't blame the mirror.
On his boat, Jordan tries to bribe Detective Denham because he thinks anyone can be bought. Well, he's basically right. Almost anyone can. As the manager of Investor Center says, "These people actually think they can get rich quick." Look at the poor mother who Jordon helped out by giving her a job and 20,000 dollars for her kid's tuition. He turned her into a ruthless thief whose sole job is to steal money from other people in similar positions that she was in. What does Mark Hanna tell Jordon in the beginning of the film? The customers get addicted to the money, so they keep buying. Everyone is for sale! So after Denham gets what he wants; Stratton Oakmont basically disemboweled and Jordon Belford put in jail… what is his reward for being so morally good? Well listen to the song while Denham rides the subway at the end. The beautiful "Mrs. Robinson" plays. But listen to the particular lyric in that scene: "Every way you look at it you lose." That sums it up quite well. Basically anyone in this society can be bought, and the few honest people who are able to keep their humanity get nothing in return but a shitty, sweaty, subway ride home.