The quotation marks are based on the fact that the new Paul VI rites of ordination and episcopal consecration were changed substantially to the point where they are, at best, doubtfully valid.
So, the quotation marks are to show that it is questionable whether Bishop Athanasius is actually a bishop, not about what he may or may not have done.
Went to a Catholic ordination of an Episcopal retread. It was strange seeing his wife attend. O tempo o mores.