"Russian state television completely ignored the protests in their broadcasts on Sunday, and authorities didn’t comment on it in any way."
I read a similar comment in CBC's article on the protests. Only problem, though, is that it's False. I checked up various state-related Russian news, and I found lots of video and article coverage of the protests - not just Alexei Navalny's arrest.
So, it is clear to me that this is yet again a coordinated Western propaganda effort, which intended to put out a false claim that, I suppose, they must have expected people to believe without anyone looking into it to verify.