On the contrary, nothing about interpretative charity prevents strong disagreement, despite any conventional wisdom otherwise from the blogosphere. The basic idea of interpretative charity is this: I interpret a thinker under the assumption that they have every intention of being coherent and reasonable in what they say, and that as a result of this intention there's probably a good bit of coherence and reasonableness that can actually be granted to them before simply dismissing their thought as so much nonsense. In a very mundane sort of way, we all depend upon charity to get along with everyday communication. We fill in gaps and make implicit distinctions explicit whenever we talk with someone, simply because we're charitable enough to assume that they have basic communicative abilities and intend these sorts of things in the first place. Interpretative charity simply assumes the same about higher levels of discourse... that if a thought is compelling or meaningful for someone else, there's probably some level of coherence and reasonableness that would at least make it reproducible and recognizable in my own thinking (if not always equally compelling).
Alain Badiou articulates something like this in The Century, taking matters straight to the classic test case of Nazism:
"Allow me to raise what nowadays is a provocative, or even forbidden, question: What was the thought of the Nazis? What did the Nazis think? There is a way of always leading everything back to what the Nazis did (they undertook the extermination of the European Jews in gas chambers) that completely precludes any access to what they thought, or imagined they were thinking, in doing what they did. But refusing to think through what the Nazis themselves thought also prevents us from thinking through what they did, and consequently forbids the formulation of any real politics that would prohibit the return of their actions. As long as Nazi thinking is not itself thought through it will continue to dwell among us, unthought and therefore indestructible." (3-4)[side note: an interesting flip-side to the Nazi example is Badiou's caution against anti-political moralizing conclusions on p. 53, following his discussion of political violence]
Something like that strikes me as similar to what is meant by a charitable stance... simply a prior assumption of thinkability (and one might add in most cases, of significant coherence and reasonableness)... but it certainly doesn't prevent harsh critique. Quite the opposite, any harsh critique only really hits its mark to the extent that charity has carried the preparatory interpretation as far as it will go.
While I don't see any need to link other conversations, this post originated out of continued frustration with the idea, held by a few folks, that I can be something of an etiquette obsessed contributor to theological conversations on blogs, unwilling to ever just go out and offer a straightforward criticism. This may be the case... for the most part I don't see the draw of spending one's time arguing with others over a screen... but any such avoidance of criticism shouldn't be associated with interpretative charity. The two are quite different practices. Conflating them will just lead to making charity less appealing to theologians and theology an even more useless exercise than it has already become in some cases.
For an example of one of my own attempts at interpretive charity done for primarily critical purposes, I'd recommend reading my 2009 article, "'Fullness of the Spirit' and 'Fullness of Catholicity' in Ecclesial Communion", in IJST. The argument I make against the CDF and the sitting pope simply couldn't have been made without taking most of the paper to follow through certain arguments on the basis of their own most reasonable terms. That is, without prioritizing interpretative charity some critiques actually remain unavailable.