Do you have a source for this? The only instances of arrests I can find are things like the above (illegal arrests) or people who trespassed on private property and were arrested for that. Meanwhile I can find plenty of stories of perfectly legal thousands-strong protests, which sounds like "mass protest" to me.

> I know the scope is different, but it is also good to keep in mind that bad things don't only happen in Russia.

Yes, but it depends on the purpose of placing that emphasis. "Even in a democracy we must be vigilant" is one thing. "We shouldn't condemn Russia for their human rights abuses because we're no different" is a very different message, and one that is manifestly false.

This is the hinge on which false equivalences turn. The scope is different, they shouldn't be compared, and being able to correctly grasp and differentiate different scales of moral offense shouldn't be interpreted as "I guess they don't know bad stuff happens elsewhere." Those comparisons do more to obfuscate than clarify.

Then nothing can ever be compared, there is always going to be differences between situations. Even just cultural differences between Russia and the US.