Here's the issue:
Either the new mass is a mass, or it is not.
If it is not, then it doesn't fulfill our sunday obligation and we can NEVER go.
If it is doubtful, then we also cannot go.
Either the new mass is 100% catholic or it is not.
And it must be 100% catholic in Theology and Liturgy.
Cardinal Ottaviani said is wasn't, Fr Wathen said it wasn't, +ABL said it has issues, +W says it is ambiguous and lends one to "slide into apostasy".
So, some say it's not 100% catholic; others are unsure.
Unless the answer is a clear, 'yes, the new mass is 100% catholic' then one cannot attend. How is this so difficult? Going on 50 years, and some still cannot take a stand?
Do we make apologies for protestants and tell them to stay in their false religion? Do we make apologies for Anglicans and tell them to stay in their false religion? Did the Church make apologies for any of the Arians, or Gnostics, or any of the other heretics in the past? No. Even if one only partially denies 1 article of Faith and is 99% catholic (if one could put a number on such a thing), it means they are not catholic and they cannot be saved.
The point is not to condemn, but to save their souls. Can a protestant, anglican, or arian save their souls, if they hold to their errors at death? Church teaching says no. So, a novus ordo catholic cannot be saved, if they hold to their errors at death.
So, while we have the chance, we must do all in our power to tell them they are in danger and to leave the new church and to come to tradition. We can't spend our energy trying to explain why "it's not their fault". We can't make apologies for their situation - they are in spiritual danger! We must warn them! We must teach them!
If clerics can't/won't do this, (and many, including +W have yet to take such a stance), then they are practicing a kind of 'catholic ecuмenism' towards our 'fellow novus ordo catholics'. This doesn't solve anything, it doesn't save souls, and it doesn't please God.