That's my point though, it was strictly speaking a pure threshold effect applied to a church. An yea, Q pointed out people live in that church, but I point out, it being a church has no deteriorating effect on said threshold. If anything it takes concrete and adds rebar
I think that is a better description of a Ward on top of a threshold, as one gets built directly on the other. The Holy Ground thing feels more like a Moat to me; a separate layer of defense at a different/outer location. Holy Ground extends to the property line (and/or the Fence in the case of a Cemetery), but the Threshold and any ward built on it ends at the Building. Which is good as Ghosts would need to be able to get to the church graveyard but not be able to bother the parishioners.
That being said, per WOJ Wards can be anchored to things besides home thresholds ("Well, you can use other kinds of similar energy structures, like ley lines, ogham stones, etc, but you can't just slap them down anywhere.") and Ogham Stones are a sort of Menhir standing stone that I could easily see being described as a druidy equivalent of Consecrated Ground. So maybe the Holy Ground aspect of a Church is just a
different energy structure that can hold a Ward, similar to but distinct from the family-based Threshold?