Because it tends to lead to public officials getting death threats or people with guns outside of their houses at night. Whatever that is, it's not rallying.
My take is that the federal government has accrued far, far more power than was ever intended. The entire population of the US has to fight over who is in charge at the federal level in order to live their lives the way they would like.
The founders had the right idea - a federation of states with a variety of laws that the people could choose among, glued together by a weak federal government.