What does it even mean to be democracy if a majority of the public believes in getting rid of something that destroys thousands of citizens every year but the government doesn't get rid of it for 9 years. As recent as a few weeks ago, federal MMJ (medical MJ) bills were discarded.
State legalization has also changed what pushing for federal legalization means. Making marijuana legal at the federal level would eliminate federal support for the remaining states where people want to keep marijuana illegal. And it would enable the development of inter-state marijuana businesses, which even people who support legalization don't necessarily support.
Another way to frame that is, you’ve reduced to snark a central question of our time.
Ultimately, I just think Rayiner has a good point about cannabis being a terrible example of the government being unresponsive.
For instance we know that inconsistent enforcement of drug laws is a civil rights issue. You could frame an argument against local choice fairly coherently on that point.
People have gotten very good at isolated themselves from others less fortunate then themselves. They can pretend it doesn't happen as they never run into personally.