His point was that the actual making of money might actually cause more harm (fraud, etc) than the good your donations would do. I don't agree; objectively weighing the harm with the benefits is possible, as other comments have pointed out.
I and 80,000 Hours take really seriously the harm you might do through your work. I'd feel very uncomfortable to say the least to recommend that someone work in Big Tobacco in order to earn to give.
I don't think of finance like I think of big tobacco though, and the criticisms I hear of finance tend to fall into one of two camps (i) lumping all of finance into one category; (ii) not really understanding what finance does. There are some areas of finance that are morally dubious (creating ever-more-arcane financial instruments that people don't understand). And I'm sympathetic in general to the idea that a lot of finance is rent-seeking, in which case you want regulation to cut down on that. But you don't have to go into dodgy areas of finance. Matt primarily takes advantage of arbitrage opportunities; it's hard to see how that is fucking over the world.
And even on the Big Tobacco front: if you could go in and substantially change their policies for the better (even if you couldn't make them any way close to perfect), I'd think of that as a really honorable thing to do. The same goes in finance. If you do find yourself in a really dodgy situation, you can always be a whistleblower, and potentially do a lot of good that way.
I like their estimate #1. For earning to give in finance to be net-negative then finance would have to be causing net harm approximately equal to all the deaths in the world.
What did you think of Brook Allen's response: http://qz.com/57807/dont-come-to-wall-street-for-the-money-e...
His point was that the actual making of money might actually cause more harm (fraud, etc) than the good your donations would do. I don't agree; objectively weighing the harm with the benefits is possible, as other comments have pointed out.