Why does a famous person saying something lend it credibility?

I've seen a lot of quotes over the years misattributed to Albert Einstein, Abraham Lincoln, Winston Churchill, etc. Why does something suddenly become wise or insightful because a famous person says it? Shouldn't a statement stand on its own two legs?|||If the legs that an answer stands on are a crooked lie, then the answer shall not stand. If a statement is widely recognized then there is much less chance that it will be debated to be a falsehood by most people. Moreover, if the person who is making the statement is widely recognized to be an honest and upstanding citizen whose contributions are of prior value to the human race then their words carry the weight of association with their deeds.|||Simple thought processes. Albert Einstein was smart. Smart people say smart things. If Einstein said something, and he was smart, the quote must be smart. Sigmund Freud postulated that all this stuff goes on in your subconscious mind. Would you trust someone guessing that it will rain, or a weatherman saying that precipitation is inevitable?