What justification was given by Whites to isolate Black men from the community and lynch them?

That freed slaves will sexually harass white women

Explanation:

Between 1882-1968, about 3,446 black men were lynched, the reasons given by the whites was that they were trying to protect the women from been sexually harassed by freed slaves. Protection of the white women was accounted to be the third largest reason for lynching of black men.