That’s a standard logical fallacy. If I wore a shirt that said “The Sky Is Blue,” does that imply I don’t think there are other things that are blue? Would people be right to insist that I wear a shirt that said “All Blue Things Are Blue?” Would people be right to assert that the ocean is blue and, since my shirt does not specifically acknowledge that, I must be in denial of the reality that the ocean is blue?
What you have constructed is known as a false dichotomy. The only reason people feel the need to point out that Black Lives Matter is because black lives have been dehumanized for hundreds of years and still are being dehumanized to this day. Black people are human beings; black people matter as much as any other group of human beings. That is the point that is being made. This should be very easy for anyone who isn’t flagrantly racist to understand.
I’ll be sure to wear my BLM shirt today in celebration of this discussion.