When a Jedi behaves badly in public, an observer might think, 'If this Jedi is a representative of the whole Order, then plainly no Jedi is worth respect.' On meeting a second Jedi, who behaves better than the first, that same person might think, 'Does this say that half the Jedi are good, and half bad?' On meeting a third Jedi, who behaves as well as the second, the person thinks, 'Was the first Jedi an exception, then?' In this way, only by the good behavior of several Jedi can the public be certain that the poor behavior of one Jedi was unusual. Thus, it takes many Jedi to undo the mistakes of one.
Odan-Urr