The difference is probably that KF mocks individuals in easy to locate and follow threads. 4-Chan's set up is just too chaotic; proving that 4-Chan is going after a specific person would be...difficult. KF organizes its mocking into easily discoverable forums and threads, which makes it easy for the individuals in question to find all the nastiness.

Finding ANYTHING with any kind of historical evidence on 4-Chan is difficult. The thousand+ posts about keffals are all collected together where she and others can read them all at once, which also contributes to making it look 'worse'.

A haystack may have more needles in it than a sewing kit, but you KNOW which ones are in the sewing kit.