I'm highly critical of Russia's current state because the government is corrupt. Not much else.Your "libertarian" ideals weep.
I'll offer one counter argument - there is absolutely no requirement for free space in a park. One can provide countless other examples of events which overcrowd NYC parks, sometimes for days at a time. How about electric zoo?
If you want orderly protesting agreed upon with local authorities - then you have Russia's current state, which you were highly critical of. The USA has (thankfully) a long standing history of allowing spontaneous gathering of large crowds.
Furthermore, yet again, have you actually gone to see these protests? Also your shorts are way too short.
Frankly the most important right (in my opinion, of course) is the right to property. Thus the owner's/public's right to property trumps the protestors right to assemble imo