Civil rights came from people of colour fighting for their life's against police and clansmen. These rights were begrudgingly granted and only after immense conflict, without which nothing would have changed.
Gay marriage was legalised after decades of intense political action that often involved physical conflict (stonewall was a riot) without the people fighting for these rights democrats wouldn't have given a shit.
The weekend was won by unions and they didn't ask nicely. The 8-hour workday likewise.
I struggle to think of anything where the democrats have been the drivers of positive change rather than begrudging portiers slowly opening a gate they'd rather keep shut.

Going further: The United States were created as a result of a violent revolution. One day they might be a functional nation