Education and good sense are two different things.

I (african-american born in northern NJ) believe ant comes from the sound, long a + ont or a-unt pronounced casually sounding like ant. Somewhere along the line some pronounced it ant with no obvious connection to aunt. In the south or southern decendents it's many times pronounced aint like the improper contraction. Which puts me in mind of my late aunt whom I referred to as Aint Thelma. It's more due to accent than preferred pronunciation.