Nobody is as accurate as they like to think about guessing who someone is based on typing style. They think they're right but most likely they're completely off the mark. You can't even use words as indicators because I know I've picked up a few words from other memers that I find myself using when I didn't before.

Subject matter is more reliable but even that isn't set in stone. I think people automatically assume that someone outspoken about a certain character has to be their RPer or another anon that is a vocal fan. Like nobody else on the meme could be talking about their character.