I thought every node accepts or rejects blocks. Doesnt add to the computational mining difficulty but doesnt it add its 2 cents to the consensus of which chain is longest/best?
That's a common myth. If your non-mining non-economic node rejects a block... nothing happens. You have zero authority. Even if all the loser nodes worked together nothing would happen.
OK but what if my non-mining non-economic node accepts a block? Doesn't that add a vote for that block? As opposed to a block rejection isn't a no vote; it's nothing.