This seems to be a recent anti-science meme to dismiss studies that use mouse models. I'm sure there is an interesting line of discussion about the strengths and limits of those models, but that's probably a complex, nuanced thread to pull, not something you blow off with a hand-waving internet comment.

To some degree the other posts are just pointing out the misleading "assumed protagonist" of the title (which doesn't mention mice) but I was surprised to see that the majority of posts boiled down to "eek! mice!"

I bet it started with people trying to 1-up other commenters via the usual “achtually…” and then proceeding with the “in mice” notice.