I see. I know there are some missions in California that function the same way, and there are also some that are more or less separate but where Catholics are allowed to have services on certain days of the year. The same applies to the Orthodox at Fort Ross.
Still, it’s pretty weird; I don’t see how he could prevent them from saying the Rosary there, if that’s all they wanted to do.
Our only source for this information is someone who thinks his “side” of Catholicism is incapable of doing anything misguided. (”Is Christ divided?” dear St. Paul ranted ...) This suggests a lack of objectivity that leaves plenty of “benefit of the doubt” for Archbishop Gomez.