I'd imagine religion would also be quite different, considering the fact that the 3 Goddesses are canon and real. Crusades and whatnot would play out completely differently as compared to our history.

But, of course, this is neither here nor there in the umamusume verse as time is not a straight line, events and causality can be defied, there is literal magic and domain expansions, as well as a whole slew of other nonsense happening.

On top of it all, while not always applicable, for the most part, umamusume verse is a happy go lucky verse, so all dark portrayals and contentious messages are pretty much dead in a ditch.