HERETICS ARE PEOPLE who hold opinions at variance with established religious beliefs. In the old days, they were burned at the stake. Their books were banned. Wars were fought against them. They were an endangered species. As time passed, they grew to be so much in the majority that the tables have turned, and now what's in danger are established religious beliefs.
It's not that the opinions of heretics on matters like the Trinity, the sacraments, and the divinity of Jesus are at variance with orthodoxy, but that they have few if any opinions on such matters at all because such matters strike them as utterly irrelevant to the human condition. They're no longer out to bring the church around to their way of thinking, because by and large they're about as interested in what the church thinks as they are in how many angels could dance on the head of a pin if there were such things as angels.
Modern-day heretics are less opposed to religion than they are simply left cold by it, and when you consider how the church more often than not proclaims the gospel—either passionlessly and unconvincingly or flamboyantly and phonily—it is no great wonder.