It's not Ikea that people hate, it's Ikea customers. People like to think of the moment they upgrades from Ikea furniture to something else as a life milestone where they ascend to another social class, and once they have done that they get to look down on the classes that buy Ikea furniture.
Sure, there's a whole list of supposed justifications, but most people's "upgrade" furniture is the same mass-produced crap, but with some marketing to position it as for the class of people who are too good for ikea. Restoration Hardware and Wayfair are making great money selling people what is essentially Ikea furniture plus a little bit of snobbery.
Heh, the first time I bought IKEA furniture I felt like a rich person, because that was the first time I even owned new furniture. Before then, all my furniture (except mattresses) came from the side of the road on large trash pickup days, or was second/third hand from relatives.
I previously would have dismissed this sort of comment with the thought "surely they are missing something." But recently we were looking for simple cabinets and found some we liked on Wayfair but just seemed expensive to me. On a whim I checked Target and found the exact same thing - same model number, even the same marketing pictures for about 33% less. The only difference, as you say, was the snobbery in the description.
Sure, there's a whole list of supposed justifications, but most people's "upgrade" furniture is the same mass-produced crap, but with some marketing to position it as for the class of people who are too good for ikea. Restoration Hardware and Wayfair are making great money selling people what is essentially Ikea furniture plus a little bit of snobbery.