Halachic autonomy

peace.
The rabbi’s approach to autonomous rulings is well known (and in particular chapter fourteen of the third book of the trilogy). I would like to ask how the rabbi relates to the story in Tractate Yoma about the Sadducees (Yoma 19:):

There was a case of a certain Sadducee who repaired the outside and brought it in. When he went out, he was very happy. His father struck him. He said to him, “Son, even though we are Sadducees, we are Pharisees.” He said to him, “All my life I have been grieving over this scripture.” ( Leviticus 16:2 ) “For in the cloud I will see the ark, and I said, ‘When will it come to me? I will fulfill it. Now that it comes to me, I will not fulfill it.’ They said, ‘There were not many days until he died and was thrown into the trash, and there were tears coming out of his nose.’ Some say, when he went out, Rabbi Chiya struck me, like a voice heard in the voice of an angel coming, and they struck him in the face. And his brothers, the priests, entered and found between his shoulders like the hoof of a calf, as it is said ( Ezekiel 1:7 ), and their feet were straight legs and their toes were flat.

It seems that the Sadducee really had good intentions and truly understood the verse differently, but there is harsh criticism here for departing from the halakha.
Is it the settlement where this is a deviation from the formal authority of that time, or is there another explanation?
Thank you very much.