Here's +Lefebvre being "subjective" in an Econe spiritual conference (i.e., New Mass is poison, but you can eat it in necessity...and it gives grace...precisely as +Williamson says):

"The father of Mr Pazat who is here told me yesterday that right now, there is not a single mass of St Pius V in Madrid. If there is no more mass of St Pius V in Madrid, if one is logical with those who are strict on the question of the mass, one would have to tell all people in Madrid that they cannot put in a foot in a church, one has to be logical, one has to be logical.. Do you feel in conscience capable to tell all people in Madrid, the whole city of Madrid, all Catholics : you cannot set foot anymore in a Church ? I do not dare saying that in such an absolute manner, since there are quite a few conditions, as I will mention, quite a few circuмstances in which we cannot attend these masses.

But there are still priests who believe, there are still priests.. the mass is not always invalid, certainly not ! If it was always an invalid mass, of course we cannot go there, if it was always a sacrilegious mass, a mass regularly sacrilegious, evidently, a mass that has a net protestant tendency, it would be evident. But I think there are at the same time circuмstances in which.. we do not know, because there is still the danger on one hand of losing the faith in the case of people who don’t go to mass for one month, two months, three months, four months, a year, they will lose the faith, it’s over, that’s obvious, we cannot make ourselves any illusions, if one were to say such to a whole city, imagine !

If on the other hand obviously you say : “But they eat meat that is poisoned !” That’s true, but if one eats a meal that is more or less poisoned, they may still last a little longer, until the moment when better nourishment arrives, while if they would die of hunger, they would be dead in three weeks or a month, they would die of hunger; It would be better to die in six months than to die in one month ! It would be better if they did not die at all, of course. But what do you expect, if not going to mass causes them to die by lack of faith, if by going to a mass that is not not very good because it is poisoning them they can prolong a little.. Take someone in a cσncєnтrαтισn cαмρ who is given a choice : either you don’t eat, and thus you will die in a short time, or you will be given meat that has gone off, knowing well that you will eat bad meat, they know quite well that it will harm them, but they eat it anyway saying : “If I can survive a little longer, maybe my deliverance will come soon !” So, that is what we must say also, maybe our deliverance will come and we will have the mass of St Pius V; it is in this spirit that we have to tell them, I think.. [end of tape]"