I think what leads a lot of people to make sedevacantism a dogma is generally a certain loneliness and isolation.
Utter nonsense. You have been repeatedly corrected regarding this slander that all sedevacantists are dogmatic and consider it to be dogma.
Secondly, having been a dogmatic sedevacantist, I can assure you that this is stupid even regarding dogmatic sedevacantists. In fact, becoming dogmatic sedevacantists leads to greater isolation and loneliness, rejection. I recall a night when I slept in the street (right on the concrete) as a result of it, and other times where I drove 10 hours to Mass, and then 10 hours back to make my Sunday obligation (driving all night to get there).
Dogmatic sedevacantism comes form taking various principles to what appear to be logical conclusions, but making the error of not "see"ing various distinctions that need to be applied.