I’ve wondered about this but I’ve never seen anyone use an emoji thumbs up in anything but yellow. I can’t imagine ever setting it to match my skin color, but it would be neat to learn about people who want emojis that look more like them.
If anything, I’d be more likely to choose a color far away from my skin.
I do it because it’s a way to personalize my message and share a bit of who I am through my text. The emojis are there to emulate my face and hands during speech, so making them look like me too is helpful to conveying a little more of what a face-to-face conversation would offer.
There was a piece on NPR saying that it's trivializing the experiences of black people. As usual, normal people don't have any problem with it, it's just a small clique of journalists and activists.
Giving the (somewhat silly) existence of all the colors of emoji, I think the best solution would be to have the software randomly pick a color every time one is displayed.