The linked memo [1] consists of a table estimating the cost for the US to secretly acquire MIGs. Stop and go read it, it's only a cover form, a table estimating the cost to get some MIGs, and a failed attempt at redacting the 3rd page, which describes the effort. The final paragraph reads:
> There is a possibility that such aircraft could be used in a deception operation designed to confuse enemy planes in the air, to launch a surprise attack against enemy installations or in a prevocation operation in which a Soviet aircraft would appear to attack U.S. or friendly installations in order to provide an excuse for U.S. intervention. If the planes were to be used in such covert operations, it would seem preferable to manufacture them in the United States.
Emphasis added. But note that the documents do not describe the mental status of the authors, they're just listing facts. Any guesses by journalists as to what the actors behind the documents were thinking or what they desired to do are only guesses.
The US government is a very, very large organization, that asks a lot of questions and produces a lot of documents. You can also expect that someone, somewhere was also tasked to answer the question "how hard would it be for the Soviet Union to procure US aircraft and launch a false flag attack against themselves, and what can/should we do to mitigate this risk." Within the Soviet government, someone else investigated what it would cost to procure some F-86 and F-4 aircraft, and what it would cost the US to get MIGs, and what they could/should do to mitigate this risk.
I would argue that it would be irresponsible of both governments to not ask these questions. I would also agree that false flag operations and indeed war itself are reprehensible, and would hope that the decision-makers, armed with this information, would still make the right choice. But given the lives, dollars, and issues at stake, and the comparably tiny cost of answering the question, it would be irresponsible not to check.
[1]: https://www.archives.gov/files/research/jfk/releases/docid-3...