It’s not confirmation bias but rather slight functional illiteracy from commenters. The original question is basically asking what’s the connection between black superheroes and having electrical powers; or in other words why is it a trope.

Nowhere in the title or the short note did OP ask people to name black superheroes without electrical powers. He only says that he saw a video that asked people to do that.

Even if you ignore the note, the title itself isn’t asking for examples of exceptions but rather for an explanation. It’s kind of like if someone asked why so many members of Congress are old and white, and the responses were just listing non-white and/or younger representatives.

This article does a pretty good job of explaining the history of black superheroes with electrical powers.

To summarize, the popularity of Black Lightning along with copyright issues lead to the creation of a few copycat heroes (ex: Black Vulcan in Super Friends, Juice from Justice League Unlimited). There’s also the possibility of electricity being a versatile power and the popularity of Storm from X-men and Static.

Someone in the comments section also noted that it could also be an artistic choice since the colors of electricity would contrast better with black characters than lighter skin characters. That seems like a stretch to me but that is another theory.

Nomacs seems to work perfectly! It even has some photo editing built in which is a nice bonus. Thanks for the recommendation!