Spike Lee's support of Bernie Sanders has nothing to do with the latest ruckus over the Grammy's. The ruckus is really much ado about nothing, and yet just another mechanism for people like Lee to make some kind of social statement. He needs to stick with making movies and leave social justice to people who know what they are talking about.
While I believe that Spike Lee is influenced and inspired by socioeconomic issues particularly when it involves race, his support of Bernie Sanders is more based on the police brutality, mass incarceration levels, and economic strife that African American communities struggle with to this day. He probably feels strongly about the Grammys and what transpired there as well, but I don't believe they are correlated.
I do not believe that Spike Lee's endorsement of Bernie Sanders is a way to support the calamity over the Grammy's. While it may SLIGHTLY be that, that is not the sole purpose. I think Lee is just trying to use whatever sway he has to ensure Trump is not voted for.
Support for a candidate with socialist leanings does NOT mean that things have suddenly changed for the better. REAL change takes time, to break into those hallowed institutions ( the Grammys included) and push outdated ideals out the door and into the burning furnace, reducing the racist ideas to mere ashes-permanently.