Andrew at Ratiocination reminds us of Plantinga's defense against de jure objections to Christianity.
Alvin Plantinga distinguishes between de jure and de facto objections to Christian belief. De facto objections say that some Christian doctrine is false, while de jure objections say that some Christian doctrine is inappropriate, irrational, or unjustified. Plantinga also famously argues that a successful de jure objection requires a successful de facto objection. The truth of the matter about Christian belief is linked to its epistemic status in at least the following way: if it’s true than it’s warranted.
Andrew dubs this the "truth connection": if an objection is true, then it is permissible to make it; otherwise, not.
Then he discusses whether the same point can be made in other contexts. For example, some current criticisms of Jerry Falwell's opinions have been decried as improper. Couldn't one think that the de jure objection, "that's improper," depends upon a de facto objection, "what Falwell believed really was false or bad."
But doesn't the context of the objection matter? For it seems there's a healthy place for observing manners and etiquette. If someone is overweight, and I tell them in front of a huge crowd that they need to lose weight, someone should tell me I'm out of line. I don't think it will do for me to say, "Well, that's just a de jure objection, but it's really true that so-and-so needs to lose weight so you ought not tell me that I shouldn't have said that."
Similarly with Falwell. I don't think people are suggesting that Hitchins might not be right about Falwell. The reasonable objection seems to be that what he's saying ought not be said right this very moment.
I take it Plantinga's response to de jure objections doesn't need to take into account contexts like this. He's discussing the rationality and truth of Christianity in abstracto.