I think I should elaborate as to why many very Orthodox Jews will not hire overly-religious/overly-zealous Catholic nannies, etc. It stems from what often happened in Europe in times past.
Often, in Europe, in countries where there was no separation of church and state, Catholic nannies would secretly baptize sick Jewish children, then report it to a priest, and the child would then be regarded as a ward of the church. Because in the eyes of the church, even a baptism performed unethically (i.e., without parental consent), remained a baptism, because their belief is that a sacrament was stilll received.
The Edgar Mortara case, in Bologna, Italy in 1858 was the most notorious exampleâŚthe child was ripped from the arms of his parents at age 6 by Swiss Guards, because the Pope said he belonged to the church now, due to his secret baptism.
I realize that in the USA we thankfully have separation of church and state and this would not happen, but many older Jews from the old country have long memories, and they pass it down to their children. So the attitude is, better safe than sorry.