The lawyer who quits a sleazy law firm to work at a nonprofit organization certainly seems like a good person. But if we define "good" as helping people, then the lawyer who stays at his law firm but donates the profit to charity is taking Cato's path of maximizing how much good he does, rather than how good he looks.

If the law firm is sleazy, then he might be actively doing harm to people while working there, and this could justify a decision to quit, or to avoid law school in the first place.

For example, he might be an ambulance-chaser whose cases clog up the courts and drive up insurance premiums, to the point that some poor people decide to drive without insurance, go to jail, and can't feed their families.

It's hard to shut up and multiply when we haven't looked at the numbers.

I see this as a flaw in the argument that might well be repairable. Otherwise, it's a great article -- upvoted twice.