The thing about boundaries is that it helps develop identity. When you’re into the ecumenical fraud known to “tear down boundaries”, it’s a scam that lets the barbarians in.
One thing that keeps the boundaries UP in Catholicism is the Liturgy.
We owe the very best to God. That means the smells, the bells, the gold, and the threads.
When we re-establish our boundaries, it’s not so much to keep people out as it is to allow them in the front door in a proper and orderly manner.