It was known that dietary fat was the cause of cardiovascular disease.

It was known that three generations of imbeciles are enough.

It was known marijuana caused Mexicans to go on murderous rampages.

It was known black men would kidnap and rape white women.

It was known the Irish bring disease.

It was known the Jews cheated us.

There’ve been many a strange fruit rotted because of some of these known harms to society.