It's tragic that a man's reputation can be sullied for centuries after his death merely as the result of the overactive imaginations of court gossips. Then again, were it not for his reputation as the murderer of Mozart, who would remember him?
But again, some of these composers have works that are firmly in the general repertoire — Biber's Mystery Sonatas, Marais' amazing suites, the Leclair 2-violin sonatas — and others are real mainstays of early-music performances. I'd say they have the approval of that long-term taste filter that we were talking about. (I'd quibble about the long-term staying power of Busoni, but the point still stands.)
Then again, part of the reputation of composers like Bach or Mozart lies in that they were able to create music of any kind their era had imagined.
(no source to hand...)