"The 1 percent preys on the 70 percent of U.S. illiterates, not because they are poor but because they don't know enough to make informed decisions."
Since when is taking advantage of people's ignorance an ethical defense of one's behavior? This is crass victim-blaming. Sure, one could argue that most profit in most businesses directly results from some sort of information asymmetry, i.e., between the two parties to any given transaction, compounded across all parties in all stages of any given value chain. But this is different. If you're offering predatory financial services and products to underinformed people who are ill-equipped to bear the risk of what you're luring them into, you are acting at best amorally. And amorality is a generous assessment in many of the cases that have come under scrutiny in recent years.
One can mount plenty of credible, justifiable arguments for banking and finance. "People are suckers" is a pretty lame one. Yes, more people ought to learn about personal finance, and about the basics of finance in general. This is partially a failure of our education system, which used to teach these things in now-ridiculed subjects like "Home Economics." (Which we ought to dust off, update, add some additional rigor to, and bring back into the standard high school curriculum. But i digress.)
No matter the case, this sort of sentiment does its author no favors. It undermines the rest of the piece, which makes legitimate points.