Despite Martin Luther King Day being an observed US federal government holiday, not everyone observes it, including companies.
One clear memory I have happened over 20 years ago, when I was working in a huge corporation in their headquarters. We were all working as if it was any normal day. Incoming came an email from the CEO harping about what an important day it was, this MLK Day. The words he wrote I can't remember but it was his action that was clear: it was so important that he didn't even bother to make sure to make it a company holiday. Unfortunately, such hypocrisy exists in many companies, not just this one.
Martin Luther King Day represents more than the man, who himself was extraordinary. Dr. King represents the ideal that no matter what you physically look like, it is what's inside of you -- such as your character -- that matters. Because we have no control over where we are born and who we are born to, but have some say on how honest we are (for example), this makes sense. Of course we are not there yet as a society but it is 2018 and it is time we try sincerely.