There’s before BLM and after BLM. What someone says depends on the context in which they say it. It’s great to say that All Kids Lives Matter in a vacuum of space. However if I am raising money for kids and said Disabled Kids Matter and your response is All Kids Lives Matter, it’s condescending. The context is key here. Over the course of history every person who has said All Lives Matter is not racist. However, we cannot separate from it’s context. As writers we should understand that.