Corn? Curses!

A woman with an allergy to corn learns that there are two differnt formulations of a promising second generation antihistimine, (antihistimines being one of the major ways one treis to deal with allergies.)

The most common version of the OTC drug lists, as its first inactive ingredient, corn starch.
The other does not! (Oh, frabjous day, etc......)
She contacts the pharmeceuitcal company to make usre of the details.
A conversation ensues.

When I asked about the differing formulations, it was explained they now make a "corn-free formulation for those who are allergic". I was then asked if I was allergic to corn and explained that I yes, I am allergic to corn.
Here's the rest of the conversation:
Me: That's great you provide a corn-free formula. I'd like to ask about the source of some of the ingredients of the formula without corn starch.
Rep: Okay.
Me: What is the source ingredient of the Magnesium Stearate?
Rep: It says here it is from a vegetable or plant source, NOT animal.
Me: Okay, what vegetable?
Rep: It doesn't say.
Me: So it could be corn.
Rep: This formula is corn free, you know that because there is no corn starch.
Me: Will the package state "corn-free"?
Rep: No, we cannot guarantee it is corn free, as we do not test for the presence of, nor absence of corn. But since there is no corn starch, you know it is corn free!
Me: Thank you for your time.
Again, that statement was, “We do not test for the presence of, nor absence of corn.” So I have to ask, what was the purpose of creating a secondary formulation just for their corn-allergic customers, if they do not know if it contains corn? Is an allergy to corn simply a marketing gimmick to them?