Even if I conceded about the illegals, (which I don’t). How do you account for all the newcomers to Catholicism? A Catholic is a Catholic, whether they are in the country illegally or not. They are not re-baptized or re-confirmed, they would be considered Catholics, new to the parish, not new Catholics.
Our parish has increased by 25% in the 8 yrs I’ve been there and I’m pretty sure there is not one illegal alien but I haven’t checked their papers. Most of that increase is converts and re-converts. We are getting young parents by the dozen, they are realizing that they want their children to have the faith handed on to them.
What increase are you talking about? Just because your parish has increased, overall Catholics have remained 25% of the population for the last 50 years. This all edged increase isn't.