Finally...An honest Catholic who will admit that it was NOT the only religion before 1600...
But one thing you forgot to mention is that while these 'heretical' churches had small issues where they disagreed with the Catholic religion, they ALL had one thing in common...They refused to submit to the Church of Rome, to the point of death...
They also refused to call the mother of Jesus the mother of God...They all refused to make Mary their queen of heaven...And most importantly, they rejected the Catholic idea of its Mass and their Eucharist...That's why these and Protestants are considered heretics...
"...they [the separate Christian movements] ALL had one thing in common...They refused to submit to the Church of Rome, to the point of death..."
That varied significantly from movement to movement. Many of the Paulicians and the Donatists, for instance, eventually reconciled with the See of Rome.
"They also refused to call the mother of Jesus the mother of God...They all refused to make Mary their queen of heaven...And most importantly, they rejected the Catholic idea of its Mass and their Eucharist...That's why these and Protestants are considered heretics..."
One again it varies from movement to movement.
As far as I know, the Donatists didn't differ from the universal Christian church on anything except their (the Donatists') rigorism in upholding the sacraments. The Donatists refused to forgive and reconcile the apostate priests and bishops who had fallen away from the faith during the persecution by Diocletian. They said that these traitors could not be forgiven, and that their sacramental ministry was invalid because of their previous sins.
Thus they did not reject the sacraments: they just mistakenly insisted that the value of the sacrament depended on the worthiness of the minister, and not solely on the action of Christ.
The Paulicians and Cathari did not honor Mary because of the association of motherhood with bodily life and therefore, in their eyes, corruption; and they did not accept sacraments because they were "spirituali" who did not accept the holiness of either the Creation or the Incarnation. They believed that all material things, including human bodies, are evil.