Stubborn, try to understand...A non-Catholic (heretic) is not a member of the Church and thus CAN'T be the head of the Church. Why is that hard for you to get?
I get it just fine. It is the dogmatic sedes who don't get that it is not their place nor they do not have the authority to claim popes are heretics therefore not a member of the Church, nor on that account that they are not popes. The whole idea that anyone can say such things is inherently anarchistic, anti-Catholic. Which is why we will remain on separate boats. You with the sedes, me with the Catholics.
Sedevacantist fr. Jenkins explained it perfectly in 20 seconds in the video I posted earlier.