The only "problem" I'd have with this, is it's very similar to saying:
The New Mass as protestant service.
A case could be made for that as well.
However, there's the point that's tricky to avoid, and that is the issue of human fallibility and ignorance.
When your church reads, "Immaculate Conception Catholic Church" it's understandable that parishioners there believe themselves to be adhering to the Catholic Church, founded by Christ in 33 AD.
And a Catholic Church offers up pleasing worship to God, not a hateful-to-God sacrilege. Everyone knows that, especially Catholics!
So no matter how protestant or evil the Novus Ordo Mass objectively is, there will always be ignorant people who think they are doing the right thing by going there. There will always be people who "don't understand" or "don't get it" when it comes to the Crisis in the Church and the exact nature of the Novus Ordo Mass.
And you or I -- or Bishop Williamson -- could give them a good spiel about why they need to reject the Novus Ordo completely. But, in the end, you can't force them to get it. You can lead a horse to water, but you can't make him drink. Frustrating, I know. But that's the way things work. You can't physically put your brain inside your subject's head, and get them to understand the Crisis as you do. Even if you're the world's best teacher, you can't guarantee results.
Trads are guilty of this all the time: Mr. Pushy Trad argues with a parishioner about something, giving it his best shot. He does his best to convince them. And at the end of the conversation, he asks, "Are you convinced?" and the person says, "No." So Mr. Pushy Trad assumes that since the "truth" was basically forced into the subject's brain and obviously rejected, the subject must necessarily be of bad will. Mr. Pushy Trad says exactly that to his fellow parishioner: "You're of bad will.
I'll pray for you." in a snide voice.
Trads. Sometimes I just want to
There is also the tricky point that the (conciliar) Catholic Church has approved the Novus Ordo Mass for the whole world. (It hasn't officially forbidden the Tridentine Mass, mostly because they CAN'T, but that's another story). Can the Catholic Church approve a Mass which is intrinsically evil for everyone to attend, even the ignorant? Can the Catholic Church approve a sacrilege for the whole world's use?
You can see why those who trek down this path almost always end with embracing sedevacantism (which includes "ecclesiavacantism" -- the belief that there is no overlap between the Catholic Church and the so-called Conciliar Church in Rome today)