"Hate to be the guy who brings up vim an an emacs thread (and trigger another round of the editor wars)" I assume.

They’re evoking the Vim vs. Emacs rivalry; like these stickers, another defunct 90’s meme.

> I do not understand what "hate to be that guy" means.

There’s usually a guy that brings up something that’s off-topic and only tangentially related to what’s being discussed, causing many people to roll their eyes.

And the thing “that guy” brings up is often something he doesn’t quite understand and why it might be annoying and derail a good conversation/thread.

That’s what being “that guy” means.

Honestly didn’t mean anything by it but I appreciate the heads up!