The same is true for the mods. Mods don't own subreddits, the community does. If they want to close down communities that aren't theirs, why not just quit Reddit? They are free to stop moderating.

That's not how it works. If you want to claim some poll as evidence of user sentiment, you have to prove that it is representative.

r/freemagic users who were banned from r/magicTCG talked about voting in the r/magicTCG poll. Apparently, mods of r/tennis posted in a Discord asking people to come help and vote to support the blackout as well. A lot of polls were mentioned in r/ModCoord which biases strongly in favor of the blackout. There’s much more incentive to brigade on the blackout side since users who don’t care about the subs in question lose nothing by those subs going private.

Eh, I gave you the clear out under #3 where you could show that these blackouts were really the will of the people. You haven't done that, if your strongest argument is about "oh, prove there was brigading", I think we're at the point where, at best for you, any polls are basically just meaningless (if they were meaningful you could use them under point #3 to refute me).