Chris Matthews is lost in a quandary. He doesn't know how to categorize Marco Rubio and Ted Cruz. Since he's a lifelong left-winger, placing humans into the proper boxes is of the utmost importance, because it's the only thing that informs his commentary. If he doesn't know what they are, it's impossible for him to formulate one of his ridiculous attacks.
Specifically, he can't figure out if Rubio and Cruz are "Hispanic." He's pretty sure they're "Cuban Nationals," but beyond that he has no idea which label he should apply, and that's upsetting his identity politics apple cart.