You were wrong. The GC law is not unconstitutional as the supreme court has stated liquor zoning laws in relation to church and school is not in violation of the establishment clause.
I might have been, however:
[So...] according to the SUPREME COURT, as long as the law is applied uniformly and does not give deciding power to a church (which it does not) it does not violate the establishment clause
The law does give "deciding power" to a church, when one wants a permit.
I guess what would then be unconstitutional, is allowing a church to obtain a liquor permit at all.