The cost of saying "All Lives Matter" in response to "Black Lives Matter" is that you are seen to be ignoring the main issue. Its not that its wrong, its that

The cost of saying "All Lives Matter" in response to "Black Lives Matter" is that you are seen to be ignoring the main issue. Its not that its wrong, its that its perhaps insensitive - a certain amount of empathy and solidarity could be a start in acknowledging the problem. So while "All Lives Matter" is truer, its less useful at the current moment in time when Black people are experiencing real pain, and we have a huge problem that needs to be addressed urgently.