This is not the doublepost you're looking for.
http://lily-orchard.tumblr.com/post/178219911855/do-you-think-itd-bigoted-for-a-white-person-to
https://archive.fo/cdG7r
One of Jerry's last few asks, relatively innocuous, but still extremely telling in the fact that he has no fucking clue what he's talking about and does no research whatsoever. Although, to give him the benefit of the doubt, he could be ignorant to it, so I could claim Hanlon's Razor, but let's do this anyway.
Jerry, they're quite literally asking if it's bigoted to cosplay as a black character. Miles is Spider-Man, sure, but they're still two completely different people with completely different costumes and slightly different powers.
Also, the most glaring difference:
They have different costumes.
So the person was asking if it would be bigoted to dress as the character on the right-hand side, since he's black. Nobody's going to assume someone dressed in that costume is Peter Parker. Except you, apparently, Jerry.
Again, he probably doesn't know the difference. He probably thinks that Miles as a character dresses up in the traditional red and blue. It's innocuous and might seem like I'm making a mountain out of a molehill, but it's still hilarious that someone like him could miss the point about something like this (a black version of a superhero who's original identity is white, something you'd figure he fellates regularly) so badly.