It’s actually rather simple. Whenever the Church uses the word cross, it means crucifix. In order to interpret that any other way, there would have to be some qualifying statements to indicate “this is an exception to the norm.”
It’s a matter of language. English has 2 distinct words, cross and crucifix. Latin simply does not.
A cross without the corpus is simply foreign to Western Catholic usage (in this context, because certainly we can find countless crosses that are not liturgical items as such).
Fr McN also said that there is lots of writing supporting a plain cross for this liturgy and that there was NOTHING in the universal church law that he could find prohibiting it. Since he shares the same personal opinion as you I think he probably looked quite hard. Further, this is being done with the ok of the bishops in many diocese which seems more than acceptable.
Like I said earlier, it seems that if we had the true cross intact to adore it would be atrocious to hang a statue of the corpus on the true cross where the true body of Christ hung.
That’s a different issue. It’s exactly why I deep qualifying my statements to say “in this context.” Certainly we have crosses without the corpus throughout the Catholic world. The pews at my parish church all have small crosses carved in the end of each one—none of them have the corpus. There are innumerable examples of plain crosses.
I’m not writing here about a cross suspended around the neck, nor in any other context. I’m writing about a cross as a specific liturgical item.