In general, upper-classish dining probably used to be more formal in the US in terms of cutlery type and placement and other things. May still be in some circles but no one I know worries about such things and even very decent restaurants don’t. And when was the last time you saw a fish fork?
My mother-in-law always used to get annoyed at me for using my knife and fork in the European manor instead of the American way. She said it was boorish. I don't know anybody else here in the US who cares in the least which way you use your knife and fork, so I always interpreted it left over behavior from her upper class DC upbringing in the 1930-40's.
(I did try to explain to her that it was more related to my being left handed than my attempting to emulate European behavior. It didn't seem to make much difference to her.)
I thought this would simply be about the knife and the fork switching hands, but holding the fork tines up or down (spearing vs scooping) is new to me.
On the other hand, I don't think Americans ever pick up food with their fork and switch the loaded fork to the other hand, especially if the food is scooped, not speared. A lot of food would be dropped in the process.
As a non-conformist, I taught myself to use my knife in the non-dominant hand so that the fork is used in the same hand regardless of knife usage.
This is bonkers. Just cut the food with your non-dominant hand. If you're so weak that you cannot cut the food with your non-dominant hand then you're either a small child, elderly, or you have a medical condition.
You obviously haven’t done it both ways and are assuming that spearing requires more dexterity than cutting. Hilarious that you could just try it for yourself and figure out that knife in the dominant hand works well but choose instead to bore everyone with your ignorance and stunning closemindedness
Do you always get fish served deboned? Cutting it with non-dominant hand sucks, especially more bony ones like trout. For me doing almost anything with my non dominant part sucks, my left hand is 20x less useful.
Just guessing here, I'm left handed also. I don't trust myself to cut a piece of steak using the knife in my right hand. So, after cutting with my left hand, I put the knife down and use my left for forking.
Or, it could be what my English son-in-law does, he uses his fork and knife, in different hands to aid in pushing food onto his fork. (He's right handed, not that it matters in this case.)