Overall I think all forms of insider trading is unethical, the financial markets are supposed to be fair playing fields where everyone has access to the same knowledge as everyone else, when you legally allow people to trade on information that others don't have access to you destroy that entire system.
Insider trading is bad no matter who is involved with it. It should be considered unethical and bad for society as a whole regardless of what the laws state. Laws don't cover everything and they certainly aren't a barometer for ethical issues or making decisions on ethical matters. Insider trading is a danger to the economy, it should be seen as such.
I agree that insider trading by member of Congress should be considered unethical even if its is consider legal. The average person is penalized for insider trading prime example: Martha Stewart and I don't think that hers issues were that bad. If it is bad and forbidden by one, then it should be forbidden by others as well.
All forms of insider trading by members of Congress is unethical. Even if the practice is deemed legal they are still governmental officials, their insider knowledge should not be allowed to influence the trading markets. It is their responsibility to be an example of excellence in the national community, so they should avoid insider trading.