"Yeah but it's still another version of Earth, and I'm pretty sure most things weren't that different..."

Weren't because the last time she'd directly dealt with the world outside Chaldea was, well, prior to coming to Chaldea. In 2015. So there's a little bit of a time difference, too. But mostly Ritsuka doesn't have the greatest research skills.

"But some of the Servants aren't human anyway, so..."

It is totally not her fault though that many of the more noteworthy ones are crazy.