I don't follow what you mean by "the actual historical reason". The article clearly indicates that 1 went through a long period of not being commonly considered a prime (for bad reasons), then a brief period of being commonly considered a prime (for bad reasons), and is now once more not considered a prime (for good reasons). It calls out the reason why we switched to the current view as being, at the very least, extremely closely related to the reason you're claiming is not "the historical reason".

Your parent comment is correct (or so close that I think correcting them is a bigger mistake); that is the reason 1 is not prime. We don't consider 1 "not prime" as an accident of history, we have the knowledge now to make an informed decision. The "historical reason" has fallen by the wayside.

This is related, by the way, to the question of 0! (zero factorial). By definition, it's 1. The most obvious reason for that is that it fills a bunch of different holes in various formulae that use factorials (Taylor series, virtually any combinatoric formula...). But that's an extremely instrumentalist approach. Is there any reason why we might predict that 0! = 1 without knowing in advance from combinatorics that we'd really like it to be the case?

Sure. What happens if we multiply together the first zero positive integers? Obviously, we get the empty product: 1. Hence the definitions I learned, where a prime number has exactly one factor (not two), and 1 has zero, not enough to be prime.

Not sure what your point is.

The OP pretty much dismisses the article and cites the one thing that is well-known, less interesting, and not the focus of the article. The article is way more interesting and lists a variety or reasons (the one the OP quotes, historical reasons, wrong reasons, and even one final twist).

The OP's comment looks like a case of "did not RTFA". Color me unimpressed.