“ The cathedral of the catholic diocese in my area also has a gift shop. It never occurred to me how that might be problematic.”
It might depend on what they sell.
I’ve visited almost all of the missions here in California. Most are still operating churches and almost all have gift shops selling it crucifixes, rosaries, saints images, books, and a large variety of similar items. I don’t see any problem with that at all. My parish is the largest in our diocese. No gift shop, but I’ll bet we almost have enough bodies to support a small gift shop. I’d have no problem if we opened one on our campus