I understand their principle. They don't to compromise with something that they see as damaging to the formation of Catholics.
It reflects an arrogance and pride that does not comport with Catholicism or even Christianity.
A separate rite would allow them to worship as they please, with their own apostolic administrators. Anyone who wishes to assist at an all-Tridentine-Rite parish could do so.
But, many ultra-trads don't want that. Just read what UR has to say.
He will tell you in no uncertain terms that a separate rite or apostolic administration is tantamount to accepting defeat.