When the Dems did it to Kavanaugh for the FIRST time, of course R's cried foul But then when the Dem candidate only months later turns out to have far worse yearbook info, they of course claim, "Hey, you guys said yearbooks count. You can't argue that it is out of bounds now that it affects your candidate".
That is not actually selectively applying it. That is just reacting to a new set of rules that were newly put forth (with understandable outrage), and then adapting to the new guidelines and using them from then on as well.
If Cole or Eli were to object to some future yearbook claim against a Republican knowing the set of rules the Dems chose to play by, and since they have now paticipated equally in the new rules, then that would be selective,
Kind of sad the Dems opened this can of worms, but the R's will play by their rules now. No more being at the disadvantage of two sets of rules for each party with the assistance of the MSM to the Dems..