Furthermore, I'm convinced it's not just some kind of fantastic cosmic coincidence that has loaded the movement with an unusually high number of charlatans and heretics. I've suggested on more than one occasion that a major reason the charismatic movement has produced more than its fair share of aberrant behavior is because the distinctive doctrines of charismatic belief foster gullibility while constantly seeding the movement with all kinds of whimsy. Specifically, the charismatic belief that it's normative for Spirit-filled Christians to receive extra-biblical divine revelation through various mystical means has opened the door for all kinds of mischief.
I would not for a moment deny that there are some relatively sane and sensible charismatics who love Scripture and generally teach sound doctrine while avoiding most of their movement's worst errors. I think they represent a fairly small minority of the worldwide charismatic community, but they do exist. A few of them are good friends—even longtime friends—of mine. I have friends (for example) in the Calvary Chapel movement, which is mildly charismatic in doctrine but whose worship is generally more Bible-centered than even the typical non-Charismatic seeker-sensitive church. As a matter of fact, my chief concern about the Calvary Chapel movement would not even be their advocacy of charismatic views, but their increasingly aggressive campaign against Calvinism.
That's not all. I have warm affection and heartfelt respect for most of the best-known Reformed charismatic leaders, including C. J. Mahaney, Wayne Grudem, and Sam Storms. I've greatly benefited from major aspects of their ministries, and I regularly recommend resources from them that I have found helpful. I've corresponded with the world-famous Brit-blogger Adrian Warnock for at least 15 years now and had breakfast with him on two occasions, and I like him very much. I'm sure we agree on far more things than we disagree about. And I'm also certain the matters we agree on—starting with the meaning of the cross—are a lot more important than the issues we disagree on, which are all secondary matters.
But that is not to suggest that the things we disagree on are non-issues.
Candor, and not a lack of charity, requires me to state this conviction plainly: The belief that extra-biblical revelation is normative does indeed "regularly and systematically breed willful gullibility, not discernment." Even the more sane and sober charismatics are not totally exempt from the tendency.
As long as Reformed charismatics justify the practice of encouraging people to proclaim "prophecies" that are unverified and unverifiable—and which frequently prove to be wrong—I'll stand by the concern [I've] expressed: even the very best of charismatics sometimes foster unwarranted and unreasonable gullibility, and gullibility about whether God has really spoken or not is seriously dangerous.
When a false belief is truly dangerous and comes replete with the kind of long and dismal track record extra-biblical revelation brings with it, it's not "uncharitable" for those who see the danger and are truly concerned about it to sound a warning rather than humming a gentle lullaby.