I have a question. Isn't this a racial stereotype? Are only negative stereotypes about black people unacceptable, but positive ones are lauded?

On a more serious note, I've heard that black and Asian people tend to have more oily skin, which is protective against wrinkling.
I don't think the youthful appearance is due to oily skin, as I believe oily, dry, and combination skin are fairly random among ethnic groups (although oily/ dry hair and hair texture/ structure is a different thing). I seriously doubt that all blacks tend toward oily skin. Skin pigmentation also varies across a wide spectrum among black people. I believe the key to having smooth, young-looking skin is generally in the melanin and perhaps something in the genes. But I also think for most people generally, it has something to do with diet and lifestyle and living as stress-free a life as possible.
My grandmother on my father's side lived to 106 (she was fair-skinned though so her long life was probably largely due to having a healthy set of genes; she had severe osteoporosis and arthritis, but generally ate extremely well throughout her life; she was an excellent cook). My grandmother on my mother's side died young from pneumonia. Meanwhile, the famous Delaney sisters lived to over 100 years of age. Neither of them married, and partly attributed their long life to that fact, in addition to practicing yoga daily.
https://en.wikipedia.org/wiki/Having_Our_Say:_The_Delany_Sisters'_First_100_Years
There's lots of positives to celebrate among all ethnic groups. And anyway, what's wrong with celebrating positives about black people? There's certainly a lot to celebrate, which usually tends to be overlooked.
BTW, if you look closely, I think it's easy to see which of the young-looking ladies in the photo is the mother. Although, she certainly doesn't look like their mother, just more like a slightly older sister.
On the issue of skin, the sun does a great deal of damage to everyone's skin, and especially so when your skin lacks protective melanin. Victorian ladies didn't wear those hats for nothing. I don't know whether this video was posted here before. I thought I might have seen it posted in another thread awhile ago, showing what skin looks like under ultraviolet light:
https://www.youtube.com/watch?v=o9BqrSAHbTc How the Sun Sees You
https://www.youtube.com/watch?v=TBEbMQzjKgc How the Sun Ages You
ETA:
Interesting scientific discovery related to melanin and it's mutation among early Europeans approximately 8,000 years ago:
http://www.ancient-origins.net/news...eloped-europe-only-recently-8000-years-020287
I don't think the simulation photo of the evolving humans that accompanies the article is exactly an accurate representation, since there were tall humans in Africa as well as in Europe. Africa is where the highest civilizations existed during ancient times.