Everyone here would totally support the bishop if the group was Catholics for Free Choice. To me, its the same thing.
I want to say, "It's not the same, because ..." but I'm having trouble filling in anything after the "because." Maybe "because they're not necessarily bad people!"
The Archbishop's point, I think, must be related to its being a public, group event of self-described Catholics. (No, I'm not making a statement about whether they are Catholic or not; the question is beyond me.) If it were a tour group from the United Methodist church seeing the historic sites, it wouldn't have the potential to create confusion regarding the Catholic Church.