Ramblings of a rural(ish) geek

It's because 'people' has taken on connotations beyond "plural of person." It's semi-odd these days to see a number ascribed to 'people'; journalists and others will go to great lengths (52 individuals, 52 players, 52 young men, etc.) to avoid putting a number before the word 'people'. 'People' means the great mass of humanity; the population of the United States; the entire race of, say, Inuits; far beyond the simple situation of being a plural form of a noun. As a result, they have begun to use a simple adaptation to mean the plural form of the noun, which is in fact grammatically correct in English. This form is more correct, in fact, if you happen to be a strict declensionist (for lack of a better word), who wants *all* nouns to become plural by the addition of 's' at the end of the noun. It's a trend.

Yeah, I don't want "women" to become "womans" or "children" turn into "childs" either, but we're headed there... :-)