But that's the underlying issue--culture. This thread is a skirmish between those who believe that the core game is multicultural enough to allow other-than-European material, and those who believe that it shouldn't. It is, at its core, an ethnic issue with a scope far beyond D&D.
1) Culture≠ethnicity. Culturally, I'm an American or Westerner. Ethnically, I'm black, Eastern European Jewish, French, Native American, Italian, German, Moroccan, Mongolian, Puerto Rican...and more. (I am human gumbo.)
2) Including the monk in the PHB leads down the slippery slope. If the monk is allowed, why not the Samurai or the Ninja? Why isn't there a core Witch class? Whale Rider? Voodoo priest? Native American Shaman?
Or to state the problem more generally: Given that the rest of the PHB classes are Western/Acultural (and ignoring the question of which classes were designed when), what is it about the Eastern archetypal monk that makes it rate inclusion in the PHB above all other Non-Western/Acultural classes published/potentially published by WOTC?
The answer: nothing.
To include non-Euro stuff like the monk in the Core book is fine...but it violates the sense of internal consistenc, and does so in a particularly arbitrary fashion.