I'm aware. Locating a single probable key is exactly not that.

Going through a list of possibilities one by one is bruee forcing.

I think it is legitimate to argue that the process here does not fit the usual definition of "brute forcing". Traditionally, brute forcing would refer to something like a dictionary attack, where an algorithm tries to match all possible combinations of words to eg. find a password. Here, the approach was more common sense based, using historical records and possible error sources to narrow down the possibility space enormously in advance, try out a much more limited set of options within that space until you got a result that made sense, and finally validate those results using historical records. It's the exact same kind of "brute forcing" a human expert would do.

Why? Because dictionary here is smaller than your idea of dictionary for brute force?

Because it wasn't an expert or a heuristic developed by an expert that made it possible to decrease the dictionary size.

If the final set of possibilities is astronomically smaller than a naive one, calling the whole process a "brute force exercise" draws attention to an astronomically insignificant part.

That’s a fair point.