Honestly I think they would justify it by saying Trump said he would pardon the Jan 6ers... Now that's a stupid idea and a terrible reason to do something since in theory, Trump could still change his mind.

I would argue since Biden and the Dems made such a point about the independence and trust they have in the judicial system that this would only hurt them in the eyes of the public. Blanket pardons in general are very rare and he already has received blowback from major players in his own party over giving his son a 10-year one instead of just on the charges he had been convicted of. According to what I can find online only once has a Presidential Blank Check Pardon been issued and that was by Ford to Nixon which was a pretty straightforward case and was done in an attempt to unite everyone again.

In my mind pardoning these people wouldn't be something they could say would be an act of unity and since they haven't been charged with anything it would be an impossible sale to the public. Just because someone is planning or might be planning something isn't grounds for a pardon (in my eyes) but it would be a perfect reason to challenge the constitutionality of fix timed pardons which we aren't even sure are legal and possibly could see Hunters pardon be blown to pieces since he was never charged with crimes in the earlier part of the 10 year window his pardon gave him.