Allowing politicians to trade stock is unusual in the "weird" sense. But certainly not unusual in the "uncommon" sense, see (1) from 3 months ago.

Insider trading laws are awful, specifically because they only restrict a specific group of people with "insider" knowledge from trading. Removing information removes efficiency (especially when you selectively pick who can act on the information).

(1) https://news.ycombinator.com/item?id=26821601