"Note here a problem: unity is achieved in the Faith. And unity cannot be achieved with an indult, a privilege that has one thing in view for some and its opposite for others. For some, the priests and faithful who want to keep the Tridentine Mass, it is a means of preserving Tradition, but for the Roman authorities – they now admit it openly – it is a means of gradually and completely bringing them over to the “conciliar Church”, to the way of thinking proper to the Church of today. All this has been established and promised in the light of the protocol signed on 5 May 1988 by Cardinal Ratzinger and Mgr. Lefebvre. Let us return to the wisdom of Msgr. Lefebvre."
January 1, 1970
https://en.wikiquote.org/wiki/Tridentine_Mass