Well, he does have a point. There is no "white history month" or "Jewish history month".
The only reason Black history month exists, and if I remember, it's a U.S. thing only- or at least the U.S. started it, was as a "we are sorry for being dicks to black people, here have a month in your honor to make up for it"
The best way to honor them? simply honor them like any other person. Based on their merits, not just on their race or because people with that skin tone had it tough.
We already honor people like MLK Jr, and Rosa Parks, and all of those people you hear about during Black History month- OUTSIDE of that month. Why? because they were either inventors, (George Washington Carver is almost synonymous with peanut Butter in the US, and found tons of other uses for Peanuts as well,) Civil Rights activists, (a topic which pertains to many nations across the globe, not just to one particular movement in the US) or other things.
When MLK said he dreamed of a future where people were judged by the content of their character, not by their skin color, im pretty sure he didn't have in mind a month where black people were celebrated just for well, being black people. A month where any black person who's done something and been somebody would be celebrated. Nah. he imagined them being celebrated, sure, but not relegated to a single month for an entire group of peoples. To be celebrated independently of some arbitrary set time frame.