I do agree that this could be an issue. I knew a guy who decided that Pius IX was a heretic and not a true pope. In that case, neither papal infallibility nor the dogma of the Immaculate Conception are actually dogmas.
Is that the guy, name escapes me at the moment, "Don" (or "Dom"?) something, who calls himself a "cardinal", wears a red zucchetto with a tuxedo, is married, and claims to be the prince of the Papal States, or something like that?
"Pope Michael" doesn't have a
thing on that guy. Some of this stuff, you could never even
begin to make up.