I don't see how working at an HFT exploits anyone more than a normal office job.
I think a better argument is that earning to give emphasizes careers that produce the "most" value as measured by the market. But there are plenty of valuable careers that the market probably undervalues, like teaching.
EA is about being data driven, and even if teachers are undervalued. (I think they are) It's probably not enough to make up for the difference in pay when that difference is donated to the most effective charities.
