Is that genuinely true of Catholics in your area? I had thought the organized structure of the brand made them far less prone to young-earth theory than non-denominated Protestants.
They do a decent job, but members of Catholicism aren’t entirely immune to psychological biases.
If you grow up as a catholic in the south, you’re in the minority. Sunday mass is just a small part of someone’s week, and you’ll spend most of your time around Protestants.
Most people are heavily influenced by their peers, and it can be pretty jarring for someone to accept that an ideology they’ve surrounded themselves with is wrong.