Because it’s a stupid comparison and a complete lack of understanding of history and racial insentivity. One is a group that was formed 150 years ago and in all 3 of its iterations it’s sole purpose was to purify America, cleansing it with White American Christian values. Using fear, intimidation, violence and political power but mainly violence. Rape, murder, lynchings, church bombings, assassinations, burning cities to the ground.
The black lives matter movement is a peaceful movement with a goal to end police brutality and expose corruption. Some protesters get violent but the movement isn’t an organized group with the sole purpose to wipe out non-blacks.