Funny, I don't see anyone complaining that Fruit Gushers hasn't taken a stand on child pornography?
I will disagree somewhat with the people who say that companies never have a place for political stuff. If you are any company involved in South Africa during apartheid you should choose a side on apartheid and voice that position.
If BLM means just the simple definition of what the words imply (that black lives matter), there's no point in saying it. Because there's literally no one on the other side. I suspect that's not what it means, because saying a broader statement "All Lives Matter" seems to be considered a kind of slur.
So "Black Lives Matter" means something deeper. More like "Black people are killed indiscriminately by police in this country. The cops get away with it, and it's a huge problem." That is full of assumptions and political beliefs that reasonable people can disagree about. And I don't see why every company should take a side on that issue.