I knew that, and i can see where they are coming from, but still see no reason to stop saying it. That is because, well, all lives matter.
To attack people over saying it is stupid. You can't just asume everyone saying it is either a racist and/or trying to spite the black community. Sure, some are, but some don't even know about the beef with black lives matter, some might, but say it anyway - simply because they mean it (and what a bad thing to mean eh?).
The way members of the black lives matter movement are going after you and trying to lynch you over twitter for saying it is ridiculous. For every racist they lynch, they lynch a caring person who just happens to not be familiar with the entire twitter sjw lore. Ironically, that lynch mob probably is a white hating racist bunch themselves.