I've often puzzled over the practice of wearing sunglasses at
inapproriate times (e.g., indoors) and especially over why this seems
most prevalent among young African-American men. What are the reasons
other than making a stylistic statement?

I remember noting that the practice seemed to have gotten a jump start
in the 60s with the Black Panthers, it having existed prior to that,
but less frequently, among black jazz musicians.

Given that our eyes have been called windows into the soul, and given
that making eye contact can be interpreted as intrusion at best,
aggression at worst (most notably in a prison environment), is not the
wearing of sunglasses indoors or on a shady day a kind of
psyche-protective device? One can scrutinize others without being seen
to do so (Secret Service agents come to mind). In any event, this
practice among young black men now seems well embedded in their
culture, and I'd be interested to know your thoughts on reasons that I
may be unaware of.

I once had a college chum who often wore sunglasses all day long to
disguise the drug-addled appearance of his eyes.

Disguise can certainly be a standalone reason, though one certainly
not limited to young black men: bank robbers and celebrities. Another
credible reason: gangsta emulation. Still another: covering crow's
feet.