Do you mean with the fork curved upwards? Or the "cut and switch" stye of using knife/fork? Cut and Switch was the preferred style in Europe until the 1800s. America is a time-capsule of some behaviors that are from 'the old world', as our habits evolved separately:
When you eat your dinner, do you keep the fork in your left hand and knife in your right, as diners in Europe do? Or do you employ the American “cut-and-switch,” putting the knife down after you cut your food and switching the fork to your right hand to eat? The latter method has been the polite...
www.thekitchn.com
The idea of criticizing someone for how they use their knife/fork is silly - and there are benefits to using it "the American way", such as more stability when piercing/mixing foods.
I'm a dual citizen UK/US, and I prefer to use the 'American method', and I'm a well-educated professionally successful human being...