This also applies to Middle eastern and African foods.
I can’t imagine my father-in-law eating either, as he insists that western utensils are required for just about everything, including pizza and fries. Finger food is not his forte and my daughter has come to resent his insistence on such decorum at the dinner table. I’ve taught her to go with the flow and use what comes naturally while being respectful of local custom.
It’s fun watching her try to use chopsticks for sushi, though, before finally giving up and using her fingers. You can’t really use a fork on maki.
Assuming I am responsible for the cleaning in either case, I disagree. I can very easily render my favourite fork (or spoon, or chopsticks, for that matter) clinically sterile. I can’t do the same to my hand without putting a rubber glove over it.
Not that I’m a germophobe, and indeed not that eating by hand bothers me - I think the whole question of what’s easiest to clean is a red herring with respect to the question you’re asking.
IMO:
Meat on the bone, sandwiches, canapes, snacks - the hand is most practical
Oriental foods prepared in bite-sized pieces, with sticky or semi-sticky rice - chopsticks
Noodles or long pasta - a long-tined fork and a spoon (chopsticks work, but it’s not pretty to watch - if that matters)
Steak, western restaurant-dinner food in general - knife and fork
Soup, stew - spoon
Horses for courses - there is no ideal single universal eating utensil, just the same as there is no ideal single universal workshop tool.
Sure you can – I ate sushi like this for a while. You can skewer the piece in the center and pop it into your mouth. Admittedly, for large pieces of makizushi, you can literally bite off more than you can chew 
Damn iPhone.
We use saws for the joints.
My thinking is that one should use whatever eating implement that was used when the cuisine in question was developed. Each kind of eating implement, whether chopstick, fork, or hand, imparts some quality to the experience of eating, through texture and flavour. And the textures and flavours in any particular dish were developed with the texture and flavour of the eating implement as a factor. So, I eat Indian food by hand, western food with a fork, Chinese and Japanese food with chopsticks, etc.
If any kind of flatbread is served with an Indian meal, it’s pretty much assumed that the bread will be used like this. However, if rice is served, then the saucy dishes will be mixed with the rice in order to make easily handled packages of food. For Indian cuisine, rice and bread are considered equally suitable for this purpose.
I like chopsticks for ANYthing, although sometimes will use a knife and fork to cut up some western food before eating with chopsticks- the only things I don’t eat with chopsticks preferred are nigiri sushi- I like to get three bites out of each, and that is hard with chopsticks…
Moving thread from IMHO to Cafe Society.