I think that message boards can work well in understanding others, but that such involves a lot more effort than most people are capable of making. How often are questions posed in a nonjudgemental way wherein there is no agenda other than a sincere desire for understanding? Imo, not often.
A great start would be understanding that different people have different preferences and that the way that each of us views something might not bear much relation to someone else's perception.
For example, some people care greatly about "realism" in a novel when it comes to weapons and combat. That is not something that I care about in any way, shape or form, but I respect that it means much more to others. So I accept that and move on. But ime others don't always do so. Some make their assessments in simple summaries that speak of "good" and "bad" and "like" and "dislike" and "well-written" and "poorly-written", when imo these things have no real meaning beyond that which the writer assigns to them.
Some people read a work like KKC, and finding one or more issues with it, or something not to their tastes, decide that the book is "over-hyped", or that it's defenders are "fanboys" or "delusional", and imo such is entirely unwarranted. Further, by this strong language those people who do enjoy it can feel attacked, and then may not be as patient in the future. It is a process that can build a divide, and then deepen and exacerbate it. And ime most observers then choose one "side" and ignore the flaws in their "side" and rail against those in the "other".
Readers who do not like it can understand why their opinions differ from others, but only by asking genuine questions and by honestly being open to understanding. Sadly, I just don't think that such is usually the case.