You can't say don't claim mixed, most african americans are mixed. Even if it's 2 or 3 generations back.
Just because someone is "mixed" last generation and you have mixed blood from 2 generation ago doesn't make you more "black" (well technically it could lol, but also could not)
mixed people are mixed, most "should" or do identify as black because they look like or have the black american experience coming up.