Because white tears cause black scars. As Emmitt Till found out

When men are seen as threats, this translates into the murder of men, particularly those who are in national minority groups. Black, brown, immigrant, Muslim, etc men are threatened by this type of discourse, at least within the United States

Which is kind of what BLM was all about - that black men are just people and are not dangerous super predators like many white people, including white women, seem to think