[Milesian]

I understand their disgust, but Sedevacantism bases itself on theology and cannon law, not just emotion.

That picture partly explains why I'm a Traditional Catholic, but it has little to say on Sedevacantism. Sedevacantism rests on the premise that a bad Pope can't be a real Pope. On the contrary, the Church itself acknowledges (and always has done) that there have been bad Popes but nowhere did it ever claim that mean they weren't real Popes. The only Anti-Popes have historically been those who were not validly elected, not anything relient on their personal character.
I believe either Bellarmine or Suarez stated that for a Pope to lose his office, he would have to be found to have been a public heretic before his Papal election to stand any chance of invalidating his position.

The problem with Sedevacantism is that it relies on the fallible laeity judging the Pope and deposing him as we see fit. To start with, the Church does not recognise the laeity to possess anything like that kind of authority.
Thus, we are led into the doctine of Private Interpretation - a heresy based on rejecting the Church's authority and which was seen as one of the prime heresies driving the Reformation (in fact, it was an old heresy revived by Luther out of necessity due to the logical outcome of his rejecting Church authority and tradition). Sedevacantism walks a very dangerous line.
I'm all for an end to liberal Novus Ordo "Catholicism", but I'm extremely reluctant to start giving myself supreme ecclesiastical authority and begin deposing Popes as I personally see fit.