Whether someone wants to participate in it or not, will still leave problems in equality.
If you're not going to give everyone they're own day/month, then why bother giving anyone a day/month at all if you're aiming for equality? Why not just have everyday be everyone's day.. universal history from every culture & race, and not just one month that's dedicated to one race of people.. Otherwise you'll get protests, and people making their own parades because they don't get a day or a month to honor their race/culture's history.
Other minorities speaking up with "What about us? .. We were treated just as badly as them, had important speakers and inventors... and we don't get our own period of appreciation?"
I myself personally, am not that bothered by it.. But I do see it as one more thing that makes us less equal. Raise the awareness of everyone's history to an equal level, a special day or month for one certain group of people, is not really necessary.