I think the problem here is this is what people in America consider a ‘comforter’
Since it’s often large enough to go over the whole bed and drape down the sides, and relatively flat, I cannot for the life of me imagine trying to wrangle that thing into a cover? They are also perfectly washable. Usually you just use that and a flat top sheet and maybe some extra blankets on top of you are cold. I can I see the confusion is that a duvet and duvet cover are just something completely different that we def do not have in America. Not to mention that the one shown above does not look like it would cover a full person comfortably and seems rather stiff? But it’s probably just a matter of what you are used to.
As for the ‘rich fancy’ label, while it is total bs to act like something from a different culture is inherently snooty or elitist, the confusion there stems from the fact that in America you just throw all your sheets and blankets in the wash together, throw them back on the bed and call it good. Poor people in America are remarkably short on time so I can see how being able to take an extra(and depending on what you mean by comforter what we would view as a very difficult) step could be seen as a privilege. Like I said with a comforter like that having to put it in something sounds very hard to me. We tend to assume that if one has extra time in the day to do things like that they must not work as much so they must make more money and therefore can take the time to do things like cook proper meals and bake and decorate their homes and do extra steps above the bare minimum to make your bed nice.
(As well as things like minimalist designes and ‘fancy’ light set ups. People who have time to decorate or can live with very little clutter in a super clean house in America tend to be the kind of people who don’t have jobs or make enough money that they aren’t being worked to the bone 60 hours a week to the point that when they come home they are often to exhausted to even put their clothes away. That’s why things like that are seen as luxurious, most of us just can’t find time to do that sort of thing.)
Additionally, a lot of very fancy beds in America have what would amount to a whole extra decorative comforter and pillows that you are supposed to take off before you get in bed, often looks like this:
So we would tend to assume that anything beyond tossing sheets and a blanket on as ‘extra’ or ‘fancy’. I cannot imagine living in a way that would allot me enough time to do THAT to my bed every morning.
However you are right just because something is different or other doesn’t mean it is inherently fancy or rich or snooty or whatever. It’s just a different way of doing things. I think the confusion is just that comforters must be different abroad and using the same name leads to a clash of what would be considered easy and what would be considered a difficult and superfluous step. As well as American work culture and poverty not allotting enough time for us to do anything above the bare minimum steps to keep our homes livable. Not to say that the cover thing is hard, it’s just that in a country where you get up at 6am and give yourself about an hour or less to get dressed and eat before working a difficult and emotionally exhausting job where you likely have to stand all day until 6-7pm and then coming home and having just enough time to eat and maybe do a few things before going to bed to do it all again, we like things to be simple, fast, and as easy as possible.
(And once again it’s not to say that a simple extra step is hard or fancy it’s just that anything above the bare minimum be it decking out your bed like you live in a luxury hotel or simply putting an extra cover on your bed is seen as equally ‘extra’.)
Edit: Most people in America also do not have acess to their own washers and driers and have to leave thier apartment or even go miles away to a coin operated laundromat and pay to wash thier clothes so a whole extra cover that would likely take up a load of its own and add a lot of extra weight to a trip would def be seen as asking too much. So yes people in America often do view being able to easily do your own laundry at home as a HUGE luxury.
