"Those who don't learn from old sayings are doomed to repeat them." :-) And they frequently do so in order to support an already spurious line of reasoning!

The average tired old saying, in fact, can be trotted out with equal facility by people on EITHER side of a fierce debate...and frequently is.

It's very silly, but that won't stop people from doing it.

Example:   "Those who don't learn from history are doomed to repeat it."

That saying can be used to justify invading Iraq (by referring to the onetime need to fight Nazi Germany)...OR...to support the idea of not invading Iraq (by referring to the debacles suffered in numerous unsuccessful wars of occupation, such as the Vietnam War or Britain's onetime occupation of Iraq, which failed miserably).

Blah! Blah! Blah! That's about all these old sayings amount to when they issue from the mouth of a biased person with an ax to grind.

They're like a gun. Anyone can pick it up and aim it in any direction he wants to. Doesn't prove a darned thing about who's right and who isn't.