Wow, that comment from Gygax in '75 is bitterly hilarious today.
I've seen much, much, MUCH more homogeneity about what the game should be and what is valid/appropriate/worthwhile in D&D from so-called "folk D&D" types than anyone else. They're the ones far more likely to be hypertraditionalists who recoil at the thought of monks (gasp!) being present in their proper* European** fantasy*** game.
*Nothing of the sort, naturally. D&D has always been transgressive.
**Ditto, what with featuring all sorts of stuff that doesn't come from Europe, and all the schizotech.
***It isn't even always fantasy.