Dear Deagus!
Did not the first post in this thread go contrary to your proposition?
"No Cardinal, by pretext or reason of any excommunication [...] can be excluded in any way from the active and passive election of the Supreme Pontiff. Moreover, we suspend such censures for the effect only of this election, even though they shall remain otherwise in force."
Fɾҽҽmαsσɳɾყ is, at least officially speaking, not a religion. That its true aims are satanic or luciferian, I definitely do believe. But this is besides the point right now. They profess no religious creed nor claim themselves to be a competitor with any other kind of faith. Therefore, a Freemason does not necessarily profess heresy.
One could possibly only claim by philosophical principle that they lose the Papacy because of their lack of intention to do the good of the community, therefore being devoid of authority. But theologically speaking, membership in Fɾҽҽmαsσɳɾყ is not heretical in itself.
Why don't we look at what that quote does and does not say, before we start saying that I'm wrong.
What it does say: No Cardinal can be excluded from the passive and active election of the Supreme Pontiff.
What it does not say: An excommunicated Cardinal can be elevated to the Papacy.
That quote, in no way whatsoever, contradicts the idea that someone who is excommunicated cannot become Pope. All it is saying, to anyone who isn't overwhelmingly dishonest, is that a person cannot be excluded from the process of electing the Supreme Pontiff, which in no way is contradictory to what I wrote. If it is, then I suppose St. Robert Bellarmine (Cardinal and Doctor of the Church) contradicts this too.
http://www.mostholyfamilymonastery.com/6_noheretic_pope.pdfBecause I can't copy paste what I want due to my mouse's failure, I suggest you read that link which says that heretics, schismatics, excommunicants, infidels, etc. cannot be Popes because they are not members of the Church.
If you are excommunicated then you are outside the Church. There is no exception to this rule, unless you would prefer to be a relativist and say that someone who is validly excommunicated is somehow inside the Church.