Fair enough, but if you buy a lot of the mayo products in the condiments aisle, the FDA doesn't think you're getting it. Check it out next time you're in the supermarket, lots of things are dressing and not mayonnaise, but I'll bet you never noticed or cared. I live with someone who's vegan so I've been paying a lot of attention to labels lately.
I feel like this is sort of the Turing test of food, given two jars, one FDA-approved and the other not. If you can't tell one from the other, aren't they both mayo?
In the extreme case, the answer is "no" - just because the flavor and texture are 'correct' doesn't mean the product is even safe. Back off from the extreme case of unsafe ingredients, and you're still not necessarily getting what was advertised. I think the question becomes "at what point should a particular formulation of a food product does it cease to be the original and start being something different."
I feel like this is sort of the Turing test of food, given two jars, one FDA-approved and the other not. If you can't tell one from the other, aren't they both mayo?