I guess for the same reason that they make cars that go 120 miles per hour. Who the heck goes that fast? Neither make sense to me.
Why do toasters have such high settings that make black burnt toast?
God created the toaster to allow us to exercise our judgement. Cooking good toast is a requirement for salvation. People who burn their toast end up on Satan's bonfire.
But fear not, there's a way out. Ogden Nash gave the formula for cooking perfect toast as, "Cook it till it burns and then, twenty seconds less."
Theres a real secret thing in the Universe that is rarely seen nowadays but is called "common sense" which is this case would be if one doesn't want burnt black toast then one wouldn't turn the setting to high. Very simple and when on burnt toast setting, one runs the chance of burning the house down along with the toast
Perhaps some like their toast black.