There are disagreements between the Catholic Church and other Christian churches on a variety of points. However, that kind of bedrock theological disagreement is not related to whether my Bishop is a turkey. (He’s not, by the way ... a fine fellow despite his unfortunate chin.)
People who call themselves Lutheran today disagree with Martin Luther on many of the key theological issues, just as people who call themselves Methodist have little in common with John and Charles Wesley.
True, but none of those men claimed to be infallible either.