Likely the most appropriate gif that's been posted yet.
Read the whole thing. It's not creating a Black persona just posting one or even 10 GIFs with Black people as the focus. It's doing it consistently. I think most people would recognize that they're doing this and question what they're trying to do. Are they trying to appropriate some sense of coolness they believe is inherent to being Black? Some people definitely are doing that.
Not on purpose mostly likely, but "Oh, hey. That's kinda cool. That person thinks I'm black because the words I'm typing and the images I'm sharing. I don't think there's any point in correcting them, though." That sorta thing. They're not trying to be hurtful, but what they're doing is not helpful.
I read the text, and I think it's pushing it a bit as a conclusion. I can't imagine people choosing reaction gifs by the color of the characters, but by the expression they want to give as «their» reaction. For instance, I can't imagine right now a better "oh, this is going to be good", popcorn gif, than the MJ one. As I can't think of a better "er...what?" gif than Drew Scanlon's one.
I have never thought of checking for patterns in the usage of gifs, or how can some people perceive me as being black or white through my use of gifs. It just feels a bit stretched, just like trying to know if I'm black or white through the music I listen to or the food I eat. We live in a cosmopolitan world where everyone can have a taste of a whole bunch of different cultural experiences and I think it's only natural to feel attracted to them.
For instance, I tend to say I love south american literature because they write in portuguese or spanish, but in a more colorful tone. Their characters and descriptions are much more vivid and exciting. Should I be worried for thinking like that?