1) Baptist Successionism was NOT believed in by the earliest Baptists. They admitted their sect was new.
2) Other Protestants admit that Baptist Successionism is untrue.
3) Baptist Successionism is completely disproven by James McGoldrick in his book called BAPTIST SUCCESSIONISM.
On the other hand,
1) The Catholic Church ALWAYS asserted and had much evidence of it ancient roots and intimate connection with the Apostles.
2) Catholics have always admitted that the Catholic Church is the true church. Only non-Catholics deny it.
3) No one can disprove the Catholic claims.
This is where I stopped reading (yes, I'll go back and finish after I type this comment). Even a little research into some of these groups, especially the Albigenses and the Cathari, should make the Baptists (and any Christian for that matter) not want to identify with them.
Every believer thinks his faith is the true.