The people of the US have more democratic rights than most other people in countries considered democracies.

This isn't true. We've got a lower democracy index than all of Western Europe, Canada, Australia, South Korea, Japan, New Zealand, Chili, and Uruguay.

As far as gerrymandering goes, states draw their own districts, and they're usually drawn by the party in power and only once a decade after the census. I'm assuming based on your instance that you're German...so try to imagine an election where everyone's only choices were between the AfD FDP (far-right proto-Nazis vs. neoliberal center-right) and whichever party won got to redraw all your voting districts. Neither of the parties really need to listen to their voters because the fascists will vote fascist no matter what, and everyone else is torn between voting for a party that's still too-right or not voting and risking the fascists taking it all. I think mosy Americans are about as culpable for the current state of things as the average German was right before Hitler was elected by about 43% of the electorate in 1933.