Mishler is known in the industry, even if many fans don't know him by name. He's a member of the "cabal", my code word for the game designers who made the "secret mailing list". So I doubt this was any sort of deliberate trolling--he was simply answering somebody's honest questions and he got
As far as GURPS goes, I'm a fan, but I'm not sure GURPS is as healthy as it once was. I remember when they were releasing 6-8 supplements a year or so and the amount of stuff coming out has really dwindled over this decade. I think they were the victim of the d20 glut--as more d20 games got popular they suffered. I'm disapppointed because I loved GURPS, but wish they'd make more supplements.
A member of Gygax's group from back in the day has contradicted your interpretation.
Wikipedia said:The owlbear is among the earliest monsters in Dungeons & Dragons and like the bulette and the rust monster, was inspired by a Hong Kong-made plastic toy purchased by Gary Gygax for use as miniature in a Chainmail game.[1]
To act as if D&D was ever a 100% non-miniature intended game is an exercise in futility.
My 2e PHB states that miniatures are 100% optional, and that, at best, they should only be used in specific conditions to make combat positioning easier. Furthermore, it states that only the DM should have a battlemap, and that the players should not ever see them.
Lastly, it recommends that, if you do use miniatures, you can use just about anything as a token, not just an official miniature.
Gygax lies, misinterprets, and obfuscates a LOT.