Sure, so authenticity is a moving target defined by the current members of a culture. I don't think that is enough justification to ignore it entirely. Regardless of how murky the definition is, surely I can say that a margherita pizza is more authentic Italian than a Domino's pie. It's a spectrum, and I am arguing more for the idea of distinguishing between large differences on the scale rather than quibbling about minor ones. I can agree that example is taking things too far without much productive purpose.
as an example, a historic cooking show I watch got a fair amount of heat for making his Scottish-descended grandmother's Scottish shortbread recipe, which used rice flour. According to the authenticity experts, this was sacrilege because no true Scottish shortbread is made with rice flour, you use corn flour. And that may very well be true in 2021, but the show managed to pull a 1929 Scottish cookbook that used rice flour in their recipe; it turns out that corn flour is now common because corn flour became extremely cheap due to American corn production, but that is a fairly recent change. https://www.youtube.com/watch?v=qnYltDdE8Cw