1) The US financial system is unsustainable. Specialize in it and you will find yourself out of a job eventually.
2) It's unethical. If you understand that your excess salary is coming from wealth that is stolen from people through the mechanism of inflation, then you may want to opt out of the corrupt system for peace of mind.
3) If the people actually understood how much they were screwed by this system, they would come after bankers, and that might include programmers at banks. This sort of happened in 2008 when bankers received threats. If the US system collapsed, they might receive more than threats. Note that, although traders and bankers are not the same, traders often use leverage with new money created by the banks and the Fed, and thus are just one hop away from the new money and are almost as culpable as the bankers. And besides, the angry hordes might not make such a subtle distinction; anyone associated with finance would be subject to retribution.