In my formative years teen years(circa 1967), I was an avid reader of Colonel Jeff Cooper in Guns & Ammo magazine. His column in the back of Guns & Ammo, he discussed his ideal pistol caliber while he was starting Thunder Ranch prior to his involvement with the Bren Ten development. {To me, Thunder Ranch is the equivalent of what the Moslems regard Mecca.} It was there that I read in his column that he wrote the specs of .40 diameter & 200 grains & 1000 fps as the minimum needed for the ideal defensive pistol round. I recall that he was very impressed with the CZ series with the slide in the frame as being a better design than the Colt frame/slide relationship. That is why the Bren Ten had the CZ slide style.
I have not read that particular interview you referenced and will defer to you that he did say that since I've also read in his columns the same sentiment about the 1911/.45ACP. His view point of what people need could be different from his ideal personal defense caliber that he was writing about in the late 1960's. After seeing several thousand people come through his facility and review probably, as a minimum, hundreds of results of having to use handguns in shooting situations; he may well have settled on that conclusion since the Bren Ten failed due to the magazine problems. In the late 60's and early 70's, was the advent of the Vunder9s with huge grips and hi-cap 9mm mags. He did diss these and the 9x19mm round in particular as being ineffective. He said that an adequately trained person can shoot a 1911a1 effectively and one .45 230gr FMJ was better than relying on multiple hits with a 9x19mm.
I see no real Kerryism{the new word for what was previously called waffling} in saying what your ideal pistol caliber would be v.s. what is the best caliber that people need.
Hopefully I've answered your questions.
Respectfully,
wganz
¶