You are so right. It is an extraordinary and unexpected experience to drive around south Phoenix and find shopping centers peppered with little Protestant store front churches with all of the signs and information written in Spanish.
I talked to the staff in my dentist's office as well as some people who attend Catholic churches in the area (all or mostly Hispanic)and they say that most of the more recent immigrants have been members of evangelical churches and had been baptized atholic were/are the product of some heavy missionary attention given to Mexicans in Mexico.
The attraction is the important positions that many may attain in the small churches as well as the fellowship that is emphasized. They also mention the fact that it is comforting to say "I believe and am saved".
correction:second para,last part of sentence:Catholic and were and are the product of heavy missionary attention and activity———.