I saw this article in another subreddit about massive public riots calling for democracy in Hong Kong. Were there ever similar protests in the USSR?
Yes during 80's and early 90's (especially during and after 1991's coup attempt) it was quite common thing. But Russians were fed up with kind of "democracy" that was build there fast enough, during 1993 there were alot more anti-government protests (with more 100.000+ protesters) that were led by Communist party and can be classified as mass public call to bring back good old days.
It ended up with Yeltsin shooting Russian parliament down.