I think it's the effect of being fantasy. Even classics like Lord of the Rings have this kind of relatable 'Medieval' characters and setting - we certainly don't hear much about the claimant border wars the Knight of Dol Amroth have, or the implications of noble rank system in an elven society. It is a choice the author can make (or not make) to stop and explore how the world like this would actually work. That's how we get Game of Thrones (which, too, is at its core fantasy, not a solemnly recreated time period - one could describe the North, for example, like the pre-Norman England in Viking decorations, while the South suddenly sports 16th century full plate armor and related customs). Fantasy can take weird one-at-a-time projects of the medieval era (like mega-ballistae, gyrocopters, or, say, ELEPHANTS WITH CANNONS ON THEIR BACKS) and make it a magic-infused standard (oh, Total War, how I loathe your Timurids)

Overall, whenever the focus doesn't need to be on the "Medieval" aspect (like Terenas's torturers, brutal barbarian societies, Gilnean and Lordaeronian feudal system and peasantry), fantasy merely plays out to morals and ideas that are relatable to the viewer.

Which is exactly why it is not medieval Kir.

There are just too many instances that are distinctly non-medieval.

Humans not killing orcs en masse after the Second War. Not even blinding them which would have been merciful by medieval standards.

Then you have this great freedom everyone seems to show, no one appears to be an out and out slave or even wage slave. And when such things happen they are isolated, condemned events. There is no true feudalism or slavery to be found!

The ability to travel quickly, a developed global mail system... Concerns over more than just food, like when A&H war over oil and such. And when we mention that what about sending armies all over the world with ease? I do not see medieval societies being able to do such stunts.

Which also reminds me how most people of Azeroth have developed nationalistic sentiments, another fairly modern ideology. Seems just about every human is willing to fight to the death rather than acknowledge any form of Horde domination. People of the medieval were much more fluid in that regard and you'd expect some commoners to bow down to the Horde or other enemies that might conquer them.

The examples go on and on. The truth is that you can't inject so many modern views and concepts without making it a modern setting masquerading as a medieval one.
I do not think anyone here is saying this is a purely modern setting, since such distinctions are unsubstantial in a fantasy setting, but it is far removed from a medieval setting as well.

Which is why I'm saying it's not either Early or Classic Medieval, but instead a world that has already gone through its revolutions, restorations and enlightenment in the past.

Compared to GoT, which is an Early M setting masquerading as a Late one.

Literacy may have been fairly high in Gilneas. Curse of the Worgen showed that Gilneas had at least one print-publishing press, and Maxwell is referred to as "local media." Books are also common in Gilneas households. Likewise, various papers and lettered-warnings of worgen could be found throughout Gilneas City and other towns.