Sure. But is that inconsistent with anything GP said? If you look at the list[1], I think you'll see that the sites are obviously not all cathedrals by that definition. The Wikipedia article doesn't claim otherwise; it calls them "sacred sites dedicated to the Archangel Michael." In fact, two of them are just islands named after St. Michael. Another is a religious site, but one that is not dedicated to St. Michael—rather it is located on Mt. Carmel which is associated with St. Michael.

[1] https://en.wikipedia.org/wiki/Saint_Michael%27s_line