For any quote you can find by a historical figure that illustrates your point, someone will ALWAYS claim that the quote was never really said by that person. Or that he was misquoted. It happens every time.
Another hitch is that even if the quote is great, and the attribution is beyond reproach, you will often have other people point out that even if the person said what you quoted, they also said things in direct opposition to that point.
People are not perfect, and while they may have said one good quote that respects liberty for all, they almost all have (or had) some very bad habits or opinions somewhere concerning some subject. Blind spots and inconsistencies are everywhere. The quoted person may have stood up for the right of everyone to own and to carry weapons everywhere they go, yet in the next breath asserted that it was OK for The State to collect "taxes" or for people to own slaves.
If I'm going to be disputed or faulted, I would rather be the target, rather than someone I can't talk to in order to get clarification. That doesn't mean I don't enjoy reading the good quotes; I do!
