What? No. There are tons of super hero masks with skin-tone on Amazon today. These ones, this one, etc. (Edit: heck, the superman beanie even has a review with a black man wearing it, I believe.)
The skinless batman and spiderman are absolutely the most common, though, I’ll grant you that.
But yes, I could have said “Obama” and “Trump” as well, as I’ve seen those too in my neighborhood, and that would take away @anon61833566’s point about whether or not it’s not a real person (which seems irrelevant, since I wouldn’t let my kid put on blackface to dress as Black Panther, regardless of whether he’s a fictional person.)