The conservatives claim they are following the example of the correction of John xxii, not any modern example. If they had said they are following the example of the theologians who objected to HV, they never would have published anything. 
Read Donum Veritatis (1990). Valid discussion for a Catholic theologian includes not "correcting" the Pope as if your position were unquestionable, but offering opinions in hopes of a deeper understanding. A "formal correction" transgresses on the Pope's authority in a way that other forms of disagreement do not. I cant remember any formal corrections attempted against JP2 or Benedict XVI.