What proof do you have that when Hispanics, or anyone else for that matter, leave the Catholic Church they automatically become Protestant? Are you claiming the voting records of those who become Muslims, secular humanists and atheists too?
Whoever said such a thing?
Hispanics that are Catholic, or that leave the Catholic church to become atheists, vote pretty similar to each other, but the ones who leave to become Protestant, become more conservative voters, such as the Hispanic Protestant vote going 56% Republican in 2004, and 48% republican in 2008.