In a blogging moment that comes across as "I can't believe I'm about to do this ... ." D. G. Hart points out that criticizing the Puritans is fine and that a defense of them independent of their acceptance of slavery is possible but that the "one strike and you're out, scorched earth" policy warranted direct address.
Hart winds up to a point that others have tried to make but have made too indirectly and too lamely. Yet Hart makes this point as someone who is not all that thrilled with the Puritans as a group.
... In other words, inherent in the anti-slavery position is not a form of genuine Christian reflection but one of perfectionism. This is a one-strike and you’re out scorched earth policy, with certain sins achieving red-letter status. If you break those, we’ll never hear from you again. This has happened with the American founders, slaveholders and chauvinists that they were, among large sectors of the academy. ...
Perhaps the best way out of this dilemma is to toughen up. After all, how happy were the early Christians hearing the apostle Paul quoted in their worship services? Wasn’t he the guy who helped kill Christians? In fact, if we apply our standards of social justice all the way through the past, we will have to close the good book altogether. The reason is that none of the Bible’s saints could withstand our moral rectitude.
Some folks attempting to defend that the Puritans can be seen as something more than just despotic evil at a certain blog seemed to be trying for this qualified defense but didn't articulate it.