Why would you cut pasta?
I can’t speak for anyone else but I do it sometimes to make the strands shorter so they won’t drip as much and ruin all my clothes.
I use my knife in my dominant hand because it’s a KNIFE. Less chance of slicing the wrong item/body part.
Shrug, AFAICT what most Europeans do is simply use knife and fork in whichever handedness they happen to prefer. Southern Europeans often grab knives less often than Americans or Northern Europeans, since we use bread to push food.
It’s one of those etiquette things that someone once wrote in a manual and a lot of other people apparently believe but which hold very little relationship with reality.
Exactly. I break in half before I cook it. 
Heh. I break mine in thirds.
I forgot to cut it into pieces before cooking it and now it’s a footlong strand ready to swing goop onto my shirt?
If you want short pasta, why not eat farfalle or fusilli or something? Why cut spaghetti or bucatini?
When I was growing up in the Midwest in the '70s, I don’t recall anyone using the term “pasta” and in people’s houses, there was only spaghetti served, no other kinds of pasta.
Spaghetti was spaghetti. It wasn’t a subset of anything. I don’t recall anyone having any other kind of pasta at home.
I saw a lot of people cutting spaghetti on their plates after mixing it with sauce, sometimes quite small, like inch-long pieces.
Thank you. In contrast to the description of the “American” method and the “European” method, this is what I refer to as the “correct”, or “sensible” method! 
For a right-handed person, eating with the fork in the right hand is of course natural, and there is no difficulty whatsoever in using a knife in the left hand for cutting – it’s not like you’re sculpting the fine details on some masterpiece; you’re using the knife to dislodge a piece of food!
Re the OP, I eat pancakes with a knife and fork, held as described.
I also can’t believe some of the attitudes about pasta! 
To me, part of the appeal of spaghetti is the long strands – it’s kind of like a texture thing. I actually prefer spaghettini rather than spaghetti – long and thin, and if the noodles were broken I’d throw them away!
Because I want the long noodle shape for how it holds the sauce. 
Yes! Yes! A thousand times yes! I’m thinking of starting a separate poll on this.
Not even mac-and-cheese?
Well of course people ate mac and cheese but it wasn’t considered to be in a category with spaghetti. It was a separate thing, with other kinds of noodle dishes. Spaghetti was considered Italian, mac and cheese not.
If you’re eating pasta like Italians do, you don’t use a spoon either. Just twirl and eat.
To the OP, as a middle-class Brit, it is ingrained in me to eat what you call ‘European style’, unless I’m eating food that doesn’t need cutting up at all, such as chilli, or pasta, which I twirl with a fork. Pancakes, omelettes, all European style here.
How about tuna casserole?
Yeah, I’ve never seen Italian-born Italians do the spoon thing, either. I wonder if it’s a regional thing, or it somehow became and Italian-American thing (which might suggest it being a Sicilian thing, but I’m not finding any evidence they do this in Sicily, either.)