philosophy

Actually, you're wrong about the Albigensians. You know, it was precisely through lies that this heresy was eradicated. For the Albigensians, the key element was the rite of consolation, coselamentum (if I spelled the Latin word correctly :D ), and those who underwent it became Perfects, who were absolutely forbidden from sinning—otherwise, they immediately ceased to be so. Consolation could only be performed by a Perfect (I wonder who the first Perfect was). The Inquisitors—by the way, they appeared specifically then and specifically to fight this heresy; they were Dominican monks—they simply approached every suspicious person and asked them, "Are you a Perfect?". If he lied, he ceased to be a Perfect; if he told the truth, he was burned. And very soon, all the Perfects were gone.
As for the Bogomils—they were the ancestors of the Albigensians; their views were quite strange overall—for example, they claimed that Evil resided in Constantinople and was embodied by the Byzantine Emperor. And, in any case, they did not lie to "their own." This is exactly what I meant regarding the degree of commonality.