Spot on.
Many people take the "Black Lives Matter" movement as being about promoting, or elevating, what is perceived to be a devaluing of their lives based on skin color. I have no problem with this, I think it is important.
While others have taken the "Black Lives Matter" movement and treat it as "My problems are so much more important to focus on than your problems, that I have no respect at all for you or your problems." I don't know what the percentage is that treat the movement like this, but I can say without distinction of right or wrong, this group receives the lion's share of media attention.
(And according to "eskimospy logic", because some people use the phrase "Black Lives Matter" in the context of my second example, therefore it is unacceptable for those who believe in the context of the first example to continue using the phrase 😛 )
In the context of the incident that sparked this thread, I would say those booing were more of the second example. Which is why I have no problem what-so-ever with someone replying with a reminder that everyone is equally important.