Right, in a traditional localized parish things are easier. Note, however, that a "very pregnant" girlfriend is just as much a public scandal as a gay "married" couple, so you did not provide a contrasting example. But there are two peculiarly Western circumstances here: (1) Roman Catholics especially in metropolitan areas attend not the canonical district parish but rather the parish the parish that resonates with them; (2) when a Roman Catholic refuses communion for any reason at all, it's instantly in the media and a national issue.
In all honesty, the "gay marriage" part is no more (or less) a "public scandal" as we are using the term than an Orthodox person "married" in a non sacramental manner by some ecclesial community, at least insofar as The Church is concerned. Neither are marriage, Alex, and both bar one from communion.
I have a friend who has been a Latin priest I'd say 50 years. He always maintained that once a parish got to 200-250 families, it was time to open a new one otherwise the fact of "community" of the assembly of the People of God, gets lost.