He doesn't know them.
Floyd Mayweather needs to read up on the pop girls. The undefeated champion boxer was quizzed on what his favorite songs by Taylor Swift, Demi Lovato, Ariana Grande, Selena Gomez and Fifth Harmony were. He couldn't name a single song by any of them, and had literally no idea who Fifth Harmony was.
Taylor: "I don’t know no Taylor Swift song."
Demi: "I like all her music"
Ariana: "I don’t know Aria Grande. What’s her name? I barely even f--king know her name."
Selena: "Ain’t that Justin Bieber ex girl?"
Fifth Harmony: "Who the f--k is that?"
I laughed ¯\_(ツ)_/¯. Watch: