If every person commemorated for exceptional achievement is to be pulled down from his plinth because he is subsequently found to have been less than a saint (according to current conceptions of sanctity), we shall end up honoring no one except ourselves. - Theodore Dalrymple
Honoring no one except ourselves - I'm pretty sure that's actually the point. The lack of actual virtue makes people starved for comparative virtue. The dead are the easiest community of all to mock and dismiss. They're not here to defend themselves.