The point was that he was comparing a striker under partial tension to a hammer hanging on a sear. I'm familiar with the firing pin block.
And since it takes a trigger stroke to fully cock and fire each and every round with the Glock, why would it NOT be considered double action? I agree that the ATF isn't exactly the depository of gun knowledge... just illustrating that even they recognize the fact that the Glock isn't SA...
I think you got my points and just wanted to post something.