French supermarkets all have very large and wide selection of "free from" style products for allergies and intolerances - gluten free, milk free. Plus vegan and vegetarian. In fact it would put most supermarkets in the US to shame. I also expect that many cafes in Paris cater for people with allergies.
So it's not that. More likely it's a surly waiter, or a tourist asking for something which is not on the menu and being upset by the answer.
Of course Chinese automakers threaten the US industry. Much like Japanese automakers did in the 70s and 80s. And there is a simple reason for that - Chinese cars makers are selling decent quality vehicles for less money than US (& European) automakers. And they're spearheading electric vehicles while the likes of Ford is actually cutting back on EV commitments.