Grocery stores - people are constantly moving around. They go in, they get their sh*t, and they leave. They don't sit there for an hour + elbow to elbow with 200-400 people, all breathing in each other's funk, possibly drinking out of the same chalice, being given a wafer by the priest who either drops it in their mouth or their hand? And before you say "not all churches do that," who's going to regulate these pastors once their flock gets in there? There's no six feet rule possible.