Are you saying that a Catholic can believe everything if he wants to or nothing if he wants to or anything in between and still call himself a Catholic?
In other words, every member of the human race is a Catholic even if they are unaware of it?
In order to call themselves Catholics, converts have to solemnly declare that they assent to everything the Catholic Church teaches. Does this requirement not apply to cradle Catholics; converts may not hold "differing opinions" whilst cradle Catholics are free to hold "differing opinions?