Members of Congress are allowed to invest in stocks right as they exit the chamber where they voted in a way that would benefit or hurt sectors or specific companies.

Some would argue "yes, but the votes are public so everyone can take advantage of them", but by the time the general public has that opportunity, both politicians and then automated stock trading algorithms have acted to make it far less advantageous if at all.

If you STILL don't get that insider trading is in effect legal for Congress (as bribes are), check out how they keep outperforming the market despite very few of them having professional background in stock trading.

The STOCK act is just toothless ass-covering or, put in another way, a bandage put on a broken leg for appearances' sake.