“Try and find a former Catholic theologian that finally said he had been wrong his whole life so he decided to become a baptist, pentacostal, presbyterian, lutheran, whatever.”
Well, wait a minute. I don’t know about “a former Catholic theologian” but there’s Richard Bennett - a former Catholic priest - who I believe is now Baptist or Presbyterian (or Reformed Baptist). There are others out there too.
Most priest that left the faith for left to get married.