My short answer is that I care for three reasons. First, since I’m not wise, it’s important to me to know what smart, thoughtful people think. Second, that these smart, thoughtful people stand at the fountainhead of the tradition to which I am heir and the regime that formed (or deformed) me helps me understand who I am. They also provide a yardstick or standard against which current circumstances can be measured. The authority of the standard is of course not absolute, but it seems to me that we need good reasons to depart from it. Stated another way, unless we’re conscious or self-conscious about our circumstances, we’re not free in the way Chris Eberle seems to think he is.
Third, and finally, I learned from Plato and Aristotle that "prejudice" or settled opinion plays a powerful role in politics, that politics, in other words, isn’t fully rational. For the most part, if we don’t honor our ancestors, we’re going to honor (and flatter and gratify) ourselves. And that’s a pretty good reason to care what the founders thought.
Update: There are good responses over at MOJ.