If you need to be X race to talk about Racial Issues, then that is where the issues begin.
But you need to. If you took a slave and a slave owner and asked them for their opinions, you'd get this:
Slave: I've been oppressed my entire life and treated like dirt
Slave owner: Black people aren't people and should be enslaved by us superior whites.
The core of the issue is purely racial, and the slave's opinion is more qualified because they are experiencing the racial issue. In this case, the racial issue is directed against one race, so whoever is on the receiving side of the racial issue has the say because they are the victim.
In the case of saying 'monday' it's just an overall offensive and insulting word. Not even black people use it, unless they're joking or something. It's just wrong to say in general, and you don't need a qualified person to prove that.