You question was basically “hey, why does only this specific demographic do this?” Then you acted surprised when a bunch of people said “lots of other people do it, too.” When you insisted you’ve only ever seen that particular demographic do it, it seems reasonable to suggest you ask a member of that group. Especially once you go onto a forum like this and nobody knows, and in fact largely disagree with your premise.
Persons of mixed racial heritage suffer confusion regarding telephony.
People like that got no place in a bad stand-up routine. 
What’s it called when a joke contains the answer? I’ll put it a different way: “It looks cool”, and furthermore, much like White folks want to embrace rap music and calling each other “Homey” and “Peeps”, I’m of the opinion that most of the White folks that do the jaunty cell-phone tilt also say “What Up?” and “Oh, hell no!”.
This should come as no surprise, since White folks have been desperately imitating Black culture for decades, from J.P. “Big Bopper” Richardson to Miley Cyrus, White folks have been giving life to the wise old saying: “Imitation is the most sincere form of flattery.”
Word up, Homes.
I don’t think it’s a black guy thing but this thread reminded me of the time I was driving down the interstate and I got slowly passed by a big 4 door sedan, inhabited in this particular case, by four young black guys. All four were slouched against thier respective doors and all four had cell phones held to thier ears. The two on the driver’s side had them against thier left ears, the guys on the passenger side had them against thier right ears. At first I assumed they were talking to each other. If not that must have been confusing inside the vehicle.
I’ve seen well dressed teens out on Friday and Saturday night - clearly on a date - where both of them are speaking or texting on their respective phones.
Call me old, but if my date started texting or talking to someone else on their phone, I’d pretty much go straight to wrapping up the date.
Could his cell phone have been on speaker? When I do that, the speaker on the bottom of the phone is activated. Sometimes when I am driving, I find I can hear better with the phone on speaker and held in just the way you describe. Sadly, I am not a young black man.
I’ve gone to meetups where people spent the whole time doing that too.
Come to think of it… Are there any young black males on the SDMB?
Serious question, folks.
Yes.
(Well, if an immature mid-30’s qualifies as young.)
Don’t know if holding your phone at a jaunty angle is a black guy thing. I’ve never paid enough attention to phone angles for me to comment.
If it was an intentional affectation, I’d say it falls into the realm of ‘trying too hard.’
Shh shh shh oh my God do not turn around but there is one right behind you HEYYYY! Ah… what it is, my main man?