The very people whose job it should be to stop this sort of thing are the ones who are profiting from it. How do you change this? No really, how can we force congress to change the rules so that elected officials can't profit from inside information? Why would they ever vote for such a bill?
https://www.politico.com/news/2020/12/18/elizabeth-warren-st... https://www.warren.senate.gov/imo/media/doc/Anti-Corruption%...
Note that the house majority leader is also one of the biggest winner of these rules not existing.