Mad dogs and Englishmen.
This is why it’s better to avoid jargon and say ‘take a siesta and stay up later in the evening’ rather than ‘biphasic sleep patterns’. (And to say ‘daylight hours’ rather than ‘photoperiod’.)
As for the OP, it’s probably due to more PoCs doing gig work and other jobs that don’t follow office hours. Whites may also be more nervous about being out late at night.