If the argument is that we get to do whatever we want because we're in charge, which seems to be the case since the justification from 2016 apparently was a farce, then the same should hold for Democrats if/when they have the opportunity. Not that I agree with that justification, of course. I'm sure the democrats would add a couple justices to the court and frame it as providing equal representation on the court given that the majority of voters in the country do seem to lean that way.
When was the last time, prior to 2016, that a SCOTUS nominee didn't receive a vote at all? Looks to me like it was 1853. No one seems to care about that. Precedent means nothing anymore.