"Heresy" is a meaningless buzzword; it only conveys that the person who uses it dislikes the teachings of the group he's attacking. It comes from the Greek haeresis, which seems originally to have meant "choice" but came to refer to philosophical schools and religious subdivisions.
The Greek word was used by Church writers in reference to various sects, schools, etc. in the New Testament: the Sadducees, the Pharisees, and even the Christians, as sects of Judaism. Hence the meaning "unorthodox religious sect or doctrine" in the Latin word as used by Christian writers in Late Latin. But in English bibles it usually is translated 'sect.'
Like other neutral words, "sect" and "heresy" became pejoratives, as with Hedges here. The philosopher Walter Kaufmann tried to reclaim the term in his 1961 book The Faith of a Heretic, but though I understood what he was trying to do I never found his redefinition persuasive or useful. The thing to remember is that "heretics" almost always consider themselves to be truly orthodox, and their critics to be the true heretics. Christianity itself originated as a sect of Judaism, and the early Christians quickly claimed to be true Judaism, even after their sect became almost exclusively made up of gentiles. This is the sort of thing Hedges should have learned during his three years at Harvard Divinity School, which was originally founded by Puritan heretics (who'd broken with the Anglican heresy) four centuries ago. Evidently he didn't, and apart from self-righteousness I wonder what he did learn there.
This is a minor criticism. The major one is that Harvard is an elite school whose function is to train imperialists and captains of industry. The "worst aspects of American imperialism, capitalism, chauvinism, violence and bigotry" were "acculturated into the Christian religion" long before fundamentalism become a potent political force in the United States, and Harvard-schooled divines were part of that process. Hedges must know that American Christianity has always been used to justify expansion and imperialism, from the Pilgrim fathers onward. Before the English arrived in the Western hemisphere, Spanish and other European imperialists claimed it with the blessing of Roman Catholicism. And before that, Christian imperialism spread by the sword throughout Europe and parts of Asia and Africa. What you might call Christian spiritual imperialism, the conviction that all nations belonged to Christ, also played a role: once the sect achieved political power, it was hardly surprising that it would "acculturate" state violence according to the flesh into orthodoxy as well.
None of this should be news to Chris Hedges; in another context he'd probably bring up these little matters himself. But he's on a roll, he's pandering to his audience (note the reactions in the transcript), and no doubt he was full of the Holy Spirit. (The presenter, Robert Scheer, suggests that Hedges is a "prophetic voice." It might be true -- prophets aren't known for their coherence or rationality.) Demonizing your opponents is fine when you're the good guy.
To his credit, Hedges attacked the Christian president Barack Obama many times, even though Obama is not a fundamentalist in Hedges's terms. Many anti-fundamentalists fawned on Obama, and they'd probably agree with Hedges that fundamentalists are heretics. But you don't need to be a Christian to attack a bad president, and given Christianity's hopelessly mixed record on most issues, it's really irrelevant. Hedges' popularity in certain circles, I think, comes from his tell-it-like-it-is, that's-how-I-roll rhetoric, which like most such rhetoric has only a tenuous connection to facts. What matters to most people isn't factual accuracy but that let's-you-and-him-fight adrenaline rush.
