Actually, I probably share far more beliefs in common with the Catholic Church than, say, Baptists, or many American Evangelicals.
In addition, many Protestants confess with Catholics the three ecumenical creeds. In this way we express an enormous amount of agreement about what it means to be Christian.
To then say Catholics are not Christian indicts the Protestant leveling the charge, because our faith is so closely linked.
As for Protestants being heretics, I believe the only way one is a heretic is to have been Catholic, and then expressed a heretical beliefs. Cradle Protestants may hold heretical beliefs, in the Catholic view, but they cannot be charged with heresy. (If I’m wrong, someone please correct me.)
Jon