I think it's a two fold problem, newbies post without searching, others hi-jack threads, both of those actions make the search feature more difficult to sift thru. which in turn makes people give up quicker and start a new post.
I frequent a few forums, JF and jeeps are new to me. but this same problem exists on nearly all of them.
I think more people need to learn how to ignore and move past the things that annoy them instead of sitting there and picking on it making a big scene, and in turn making just as much clutter as the person they got annoyed at in the first place.