As with anything else you need to take Schillings comments in the vein that they were said.
He is simply pointing out that they flew their P-40s to their strengths, and that it had some attributes (some, not all, not uber, some) that made it effective in fighting Ki-43s, Ki-27s, and other IJ a/c that were of that type of manueverbility (like an A6M).
Its what all successfull pilots did, they found what tactics worked with what they had.
Im sure a lot of ex AVG or USAAF pilots who flew P-40s in the Far East and Pacific that were good at it chaffed at all the post war glamorization of the P-38 and Corsair, and felt that "we did ok with what we had". Its hardly a surprising sentiment.