Again, that's a reason to punish Pelosi and others who violate the rule. It's not a reason to punish people who haven't done anything wrong.
I don't know why you're telling me anything about gun control. Isn't this the very argument against gun control. Seems like a worthless rhetorical point to say "They want this for gun control therefore it should apply to buying stocks." But I'll address the flaw here anyway -- if they implemented gun control, if would affect everyone, including us and themselves. What is being discussed with stocks is not affecting everyone, it would not affect us. Just bad rhetorical point.
anyway, a compelling reason to prevent congresspeople who have done nothing wrong from participating in the free market is that some other congresspeople abuse the free market?
By that logic, no one in Congress should be allowed to do anything. I'm sure there are Congresspeople who use their position to get themselves all sorts of sweetheart deals. Discounts on cars - no Congresspeople should be allowed to by their own car. Real estate opportunities - no Congressperson should be allowed to buy real estate. Free box seats to sporting events - no Congressperson should be allowed to attend live sports.
If the argument is "Some people in Congress break the rule, therefore no member of Congress should participate in that part of the economy," then that is a very broadly applicable rule. And if it's just stocks, what makes stocks the one area where this rule is okay if it's not okay elsewhere? That's what I mean by a compelling argument.