So, in this dispute ...
#1) Sean, CK didn't call it a "dogma" but a "doctrine".
#2) CK, Pius XII taught that the sin of heresy separates from the Church, but he didn't stipulate what kind of heresy, manifest, notorious, public, declared, etc. He left the details of that controversy unsettled.
Nevertheless, +Schneider denies that ANY type of heresy: apostasy, profession of a false religion, manifest, public, notorious, declared ... he denies that any of these would remove the man from the Church, and therefore from the papacy, so the criticism of +Schneider as denying this doctrine does stand, as +Schneider covers the entire gamut of every side of the controversy ... except for the "once Catholic, always Catholic by virtue of the Baptismal character", which does appear incompatible now with the teaching of Pius XII.