Something to keep in mind is that there is no denying there were knuckleheads there that day who broke stuff and who you could say "rioted" to some extent or another. From what I have seen, they have, for the most part, been getting hefty fines and/or sentences in the 1-5 year range. There may be some who have gotten more, but this is what I've seen.
The two decade sentences are going to people that never entered the building or were not anywhere near the Capitol at all. Because of, as Dogmush alluded to, wrongthink.
I too, hope an R with balls gets in to commute or pardon most of these sentences. Or at least looks at fair retrials. Even better, additionally investigate the prosecutors and judges for their bias and for the jury trials all taking place in DC, with juries NOT of the defendants' peers. It'll never happen, but one can hope.