There are a lot of “manners” that existed only as fashion. They were nonintuitive by design, so one could tell the anointed and connected from the baser classes. A good example is the pinky when holding a glass. There is no practical reason, and it’s no longer de-reguer.
Emily Post, America’s icon of manners, adopted what is now considered the primary rules of manners, and they’re based on being polite, not drawing attention to oneself, and not disturbing others. So, one doesn’t cut all one’s food before digging in because that destroys the beauty of the plate. One doesn’t take butter from the butter dish directly to one’s bread, because (since presumably you’ll have to go back for more) it ties up the butter dish. Instead, put the butter on your bread plate and allow it to move to the next diner.
I don’t know anything specific about the soup spoon busines, but I do seem to remember it, along with tilting the bowl away from you (and I can’t quite remember if it only applies when tiltin the bowl). I’m guessing here (sorry, on GC forum!) but I suspect it’s a case of the pinky thing: no practical reason, just something to be “distinctive of class” as they say.
Post’s best example of following the fundamentals rather than the specifics is a story of the Queen of England, when hosting some Oriental dignitary or royal (IIRC, a son of the Japanese Emperor). There were finger bowls to wash ones fingers after certain dishes, but the honoree didn’t know this. At the end of the meal, he picked his up and drank it. The attendees looked on in horror. The Queen promptly picked up hers and drank it (after which, everyone else followed suit). Classy lady, that Queen!
It is how I was taught too, and I’m in my late twenties. I think there is far less of an emphasis on table manners nowadays, so I’m sure many people don’t know or don’t think it’s important enough to do it. I just gulped down a bowl of soup behind my laptop in a most unseemly manner.
However, there are occasions (nice dinner parties) when I would certainly fall back on those manners, and many people I know would. So I do think it’s still in use, and certainly worth knowing should you find yourself at a nice dinner.
It’s to forestall spilling on to your shirt or lap.
It makes sense, and it’s counter-intuitive and more inefficient, considered in the realm of getting food into your mouth. But luckily, being humans, we do things like that countlessly, as individuals or in groups up to nations and species, because we know about different realms of “efficiency.”
Drinking the lemon soup is a standard joke, I’ve seen it from so many old movies - 3 Stooges, Prince and the Pauper, etc. I’m sure it’s an urban legend from way back.
The logic I was told was to tilt the bowl away (a bit more awkward) to get the last drops - at least if you tilt too far or scooping with the spoon makes the soup overflow, it’s not on your lap. Just common sense.
Spoon-away also slows you down, which makes meals more classy. But yes, I suspect not spilling was of greater importance among people who didn’t have washing machines, and often wore stuff that couldn’t get wet without damage.
But I only learned it as “proper”, I’ve never actually seen anyone eat soup spoon-away.
When I eat soup, I fill the spoon and carry the spoon from bowl to lip. By the time I’ve lifted it from the bowl, it hardly matters which direction I scooped. Unless I’m scooping so fast the soup is flying, but that’s not going to be polite no matter which direction. Better to splash myself than the person across from me!
Regarding the finger-bowl story, it’s just a story to illustrate a point, and it’s not terribly important whether it’s true. It has all the hallmarks of a legend, since we see it in different forms but never with enough detail to check, or any references. However, I can see with google that it appears in a review, attributed to Judith Martin (Miss Manners). I probably misremembered the source.
In the last three paragraphs she explains that there was once a practical reason, a need to minimize finger contact because teacups were thin, transmitted heat easily, and had no handles. After teacups began to have handles,
Miss Manners says to tip the bowl away from you, and this is the reason why. I do not have a date but she published this in a column several years ago. She did not say that every spoonful had to be scooped away from you, though.
That’s what courtesy plates are for (the dish under the bowl or under the soup dish). Since you do not lift the bowl from the courtesy plate and unless you insist in staying perfectly stiff or have a large chest, the path from bowl to mouth goes exclusively over the plate - it does not go over the linens, much less over the eater.
The only place where I’ve heard of the bowl-back or spoon-back things has been in the Dope (this isn’t the first time).
Spoon-away not only avoids the risk of spilling soup onto your lap, it means that when you bring the spoon to your mouth, you’re sipping the soup off the clean side of the bowl - and are less likely to get a drip of soup on your chin or beard.