Catechism of the Catholic Church
The Church speaks doctrinally with one voice.
Those who dissent from dogmatic Church teaching are material heretics, at the very least.
I would emphatically agree with you that they are/should be considered heretics as defined by dogmatic Catholic teaching. Still, I've heard quite a few, shall we say unusual things from FRCatholics that I would think (hope) are heretical by Catholic standards. At the very least they contradict equally dogmatic statements made by other FRCatholics. Drop by the Luther/Erasmus thread sometime to get a sample of what I'm talking about.
The only other possibility I can envision is that what Rome considers "dogmatic Catholic teaching" allows for a far broader and looser layperson interpretation, than what we Protestants think "dogmatic Catholic teaching" allows.