This topic has come up before...
The first use I heard of the term was in the auto industry, where the basic frame was and is called the platform. So a platform can be used for a four door sedan, a convertible, a pickup truck, a delivery van, etc. The car magazines picked up the term, and it spread from there.
I believe you are correct. E.g., when I worked at Ford, we talked about the "panther platform" -- the Crown Vic, Grand Marquis, and Towncar are all the same car underneath. Just different safeties, beavertails, and more lines per inch on the front strap checkering.
So anyway, someone suggested that it's just a marketing thing. That's not entirely correct either; it's a general business or product development term. In the business world (not the military world), there is the notion of a "product platform". Google it and you'll find plenty of references to the term; about half a million. Here's an entry from businessdictionary.com
Common design, formula, or a versatile product, based on which a family (line) of products is built over time. See also sales platform.
I, personally, think it's a perfectly acceptable term, once you see its applicability in manufacturing, business, and marketing. If you confuse it with "weapons platform," the misunderstanding makes sense to me.
BTW, Tuzo said:
"Gender" when "sex" is proper. Gender applies to grammar as in masculine and feminine. Sex denotes male and female.
This is not correct; rather, it's inappropriate pedantry. The Oxford dictionary assigns the same meaning as "sex" as the primary definition of "gender." That covers British usage. For us 'muricans, Merriam-Webster gives this as the second definition of "gender": the behavioral, cultural, or psychological traits typically associated with one sex
I'm as pedantic as it gets, but there are limits.