Saying all lives matter is fine, as long as you mean it. People have proven that all lives do not matter by supporting the corrupt police system and discriminating against people of color. If you say all lives matter and also support the corrupt police system, you can't possibly believe that all lives matter because you're supporting people who think that police brutality is okay. The black lives matter movement is not a movement focused on becoming superior, it's a movement focused on gaining equality between black people and everyone else.