I’m going to posit that he was probably focused on range. He’s right that a PPD is not exactly what you want for taking 300 meter shots with. Suggesting that it would be suitable for police would be from the mindset that police operate entirely at close range.
This ignores that volume of (reasonably accurate) fire trumps mechanical precision accuracy at long range in infantry fights, and is wrong but his wrongness isn’t unique. The cult of accuracy / cult of the rifleman is a line of thinking that pops up throughout history.
Wasnt it exactly that type of thinking that delayed the adoption of the M16 as well, even though test units liked even the shoddy prototypes they were given.
There’s no evidence that he was anything other than a very outdated military thinker. He got his military start in 1912, making many of the advancements of the 1940s seem very newfangled. He fought on the side of revolutionaries during the Russian Revolution.
You can see his outdated military opinions causing problems during the Winter War against the Finns, showing he wasn’t simply pulling punches against the Germans.