To clarify, I don't think the ban is a blanket one. It's not like people are turned away every week. I've heard of feeneyites being denied and also other random people who openly disagreed with SGG on this or that. I think the "una cuм" was used as a catch-all explanation from SGG clerics to the parishioners, to explain what happened after the fact. The point being, the SGG knew the Trads that they turned away.
The Cincy area has 3 different chapels (sspx, Fr Jenkins, +Dolan/Fr Cekada) being within 30-40 minutes of one another, all with very different Trad flavors. The controversy arises when the youngsters start dating from different chapels, because then the different clerics have to "lay down the law" on a) feenyism, b) sedevacantism, c) una cuм, d) pro-rome, e) not switching chapels, f) home school vs chapel school, g) etc etc.
SGG is definitely wrong in their "turf war" but so is the sspx and Fr Jenkins. All 3 groups have contributed to the nonsense, conflict and family turmoil. There are many, many stories where a couple got married at one of the chapels, and one of the spouses' families won't speak to them. The clerics condone and contribute to these tragedies. It's still going on.