what do you expect from a hobby invented by white boys with literal 'race' mechanics that determine your objective 'alignment' in older editions and still play into racial caricatures to this day ('noble savage' orcs instead of just murdering hordes, elves as even special-er white people) and even in the best case scenario only encourage race-based divisions whether based on stats or just aesthetic, after all its a lot more reasonable to be 'racist' against a species of literal giant green monsters with boar tusks (that even if a 'good guy' is constantly being whispered to by their Evil God that created them, in most DnD lore at least) than it is to be racist against a human with more melanin in their skin. and the usual semi-historical settings come pre-baked with implicit old-timey attitudes, people expect swords and sorcery type settings to maintain the patriarchy and nationalism pop culture associates with our own history for the most part even if Player Characters are the Special Chosen One that Bucks the Trend. I mean even outside of DnD, how many fantasy media products even cricticise monarchy? how many protagonists are the Rightful Heir that needs to reclaim their Tragically Lost Throne from the Evil Guy?

It takes effort to salvage a worthwhile story out of something like that, and a lot of people just do the easiest/laziest thing and play to the genre tropes. it's hard enough running a tabletop RPG without interrogating the system's racial biases, or that of your own writing, and most people simply won't bother. to the average non-politically aware person, the races become a visual shorthand for real life groups or assumed historical groups, 'elves' are 'cultured europeans' (french, english, etc), 'orcs' are 'misguided savages' at best, 'murdering subhuman invaders' at worst (muslims, mongols, slavic people, etc) 'gnomes' are 'incomprehensible insular artisans' (jews), 'halflings' are 'nomadic pastoralists' (roma) 'dwarves' are 'industrious europeans' (german, irish, etc.). It's obviously not the only way to write fantasy, but for most people this is what 'fantasy' means to them, a bunch of cultural and racial caricatures fighting each other with magic and swords, because its the laziest and easiest to write that way in our society, given the cultural context, genre assumptions, and history of development of the fantasy genre.