Warcraft isn't mythic. It stopped being mythic when the dwarves started mass producing firearms and Sylvanas started using chemical warfare. Actually, hell, scratch that: Warcraft stopped being "mythic" when we got globalized economies and world wars. Essentially, Warcraft is hovering around the first half of the 20th century, just with magic.

Regardless, even without the bronze dragons there ARE ways to see into the past. Off the top of my head, a draenei shaman uses some kind of shamanic herb blend to see into the past where the humans split off from the vrykul. I can imagine anyone writing a history textbook would be dropping those 'herbs' for the greatest accuracy. I know that there are also arcane based ways of seeing into the future (the archmages in Dalaran who'd give you your daily dungeon and raid quests during WotLK) and I'm pretty sure it works the other way, too.

Point is, it should not be hard to find this stuff out, lorewise. The only way you could have a "wrong" perception of history is if your government was purposefully rewriting the past in order to deliberately misinform you: something I'd expect from the fascist Forsaken or authoritarian Blood Elves, but not from the Tauren.