kill a few blacks, the younger and more innocent the better, any other ethnic group will do in a pinch....
That is the implication.
Why do people respond to "Black lives matter" with "All lives matter" or in this case "Blue live matter"? It's probably because they don't understand what "Black lives matter" means or why it exists, and they don't seem to care about figuring it out either. Why could that be? They're taking sides. They see this as a liberal cause, they see this as not their race, and so fall in the other camp. It's liberal vs. conservative, cops against blacks and it's all conflated into a horrible hodgepodge in which, I'd say, they unwittingly encourage the dehumanization and institutionalized impoverishment and murder of black people.
That's giving them the biggest benefit of the doubt. I find that I give some people around here way too much credit. It could just be that they're racists.