When a Progressive says so.

Former New Mexico Gov Bill Richardson said Sunday that Republican Sen Ted Cruz, whose father was a Cuban immigrant, should not be “defined as a Hispanic” because of his stance on immigration legislation.

Richardson justified his redefinition with this:

I don’t like his politics…. No, I don’t think he should be defined as a Hispanic[.]

Just like conservative blacks must be uppity Uncle Toms and conservative women must be sluts, so an Hispanic who holds views that are disapproved by Progressives must be drummed out and denied his heritage.

Why does the Left insist on being racist?

Because they think they can accrue political power with it, and they can get away with it.