Finally my communications degree can come out and play.

"Racism" is an emotionally loaded word. The reason it carries this punch is because people define it as specifically being "race based prejudice", not as a systemic form of social and political interactions that favor the majority (which could as easily be defined as "democracy"). It gets a reaction, which is why folks in the UK have rebranded certain forms of classism as social or cultural "racism"; and why a lot of POCs in the States are folks whose parents, up to a decade or so ago, were checking off "white" on their US Census forms. Two different definitions that set up an argument for a good-old-fashioned bait and switch.

Dictionaries are designed to be tools for communication, it standardizes the language so people are saying and interpreting things basically the same way. How can you fix a problem when no one can even agree on the definition. The artist uses the dictionary as an authority in Scrabble, it would only make sense that it would be used as a "referee" in public issues that need addressing.

Consider the definition of "white." The colloquial definition is "Caucasoid", the South American Apartheid era definition includes East Asians, and the legal definition in the US excluded the Irish (and other ethnic groups) up to the mid 1800s. The term "POC" is directly affected by that definition of "white," meaning that a person can go from being part of the oppressed class, to being a member of the oppressor class within the span of a Twitter exchange.