Race also matters to the people who are being discriminated against because of their race. Speaking about race and racism is a necessary evil sometimes. Doesn't make you a racist. Calling people racist who do it because they have to, not because they want to, is racist, though.

The impact race, something that should irrelevant, has had on society over the course of history isn't unimportant just because it should be.

Genocide doesn't stop being unimportant because the people that experienced it are dead. That should be pretty easy to understand. The same can be said about other parts of history as well, such as racism.