In addition, calling the Albigenses "Bible-believing Christians" is just silly. They were none of those things.
There have been heresies and offshoot sects all over since Pentecost. The common characteristic of them all is that they have no common characteristics, not that they were proto-Baptists.
There were too many other groups outside of Rome OR the Waldenses to reject the fact that Rome had no monopoly on being the "Church".
What IS incontestable is that Rome (and Canterbury and Moscow and Luther and Calvin) ALL sought to establish State churches - which ALL brutalized any person who sought to be independent of their rule.
God Bless America for religious freedom.