>>714537289 (OP)Flanderization.
As is known Elves in Tolkien's work likely derive from an ideal of humans potential and culture long lived, refined but one with nature, wise and skilled.
But, likely to avoid the plot ending too quickly from all these feats, usually slow to get too involved too soon, but ready to chide the other races for past or present failings.
That probably began to remind young people of the unsympathetic adults in authority who led them to escape into fantasy in the first place.
So they amped up the flaws and downplayed the virtues Tolkien had setup when they depicted them in their own TTRPGs and stories, the caricatures probably snowballed from resonating with others more than the original intention leading to perpetuations and further exaggerations in other works especially those built on satire like Warhammer.