Ideally the FDA should not be swayed by business interests, but everything controlled by our government is. That said, you want the FDA to exist and protect us from bullshit snake oil products and keep corporations from lacing our food with cheap poisons and carcinogens.
Trump gutting the organization makes it go from “could do better” to “actively subverting its own purpose.”
Basically just start with what you’re aiming to enable and work backwards (as you’ve started to do). With judicious use of grep find out where that symbol is defined. If it’s in arch configs for other arches but not your own, it’s probably that.
There may be better tools out there to do this, but in my experience just sleuthing it out a bit will answer your question. The Kconfig system can be complex, but the files are pretty readable.