That is odd logic. A judges descion can not be questioned. It is not subject to popular opinion. It is not like his vote is going to count less. The Dems would actually be stupid to filibuster simply because it will give the GOP a tool to use against the next Democratic President to stop their SC appointments. The GOP are in position to nuke the filibuster, the Dems probably would not be.
Very odd logic indees. The Dems UNANIMOUSLY confirmed Alito twice before to lesser high courts. The question would be why they were fine with him repeatedly before, then have to be dragged in the extreme just to get an up/down vote.