The problem is that he feels like he was making the bank rich and the customers didn't get much out of the deal. You're right that they provide services people

The problem is that he feels like he was making the bank rich and the customers didn't get much out of the deal. You're right that they provide services people want and need and generally speaking there isn't a problem. But in this case he was observing that the bank was able to enrich itself while providing nothing in return for the customer. That could make anyone feel bad. I hate when people beat up on something because it's popular at the moment. I honestly see both sides of this. I'm not a fan of certain banking and investment practices and some of that culture, not all of Wall Street. At the same time I feel for the author. The bit where he mentions being fired really distracted people from his main point too which I don't like seeing.