Ok, this is just my personal opinion, but those Upper Echelon Gamers (UEG) are not close enough to gacha games and/or JRPGs. Those UEG are more into the common/newer/flashy games, so that’s why they actually downloaded Genshin Impact.
-Gacha games are known for their top-rarity items/characters having absurd low rates. (Genshin Impact is not the one with the lowest appearance rates)
-JRPGs are (in)famous by their Infinity farming systems to get lots of X material, to have Z stuff upgraded / improved.
-Elemental ability system is not an original from Genshin Impact. There are other action-JRPG with this same system (a little Mobile example: Dawn of isles). So the way alemental abilities work, is reliant on team composition in Genshin Impact. You will need different characters (with different elements) swapping from your team-comp. according to the enemy you are going to attack. (As in many other RPGs).
Genshin Impact is not innovating in anything special within the genre. They have this anime style characters, an “open map”, the stamina system to perform certain actions while exploring maps. Monsters roaming from place to place, dungeons, missions and quests. All of the aforementioned characteristics sound like every other RPG.
What Genshin Impact have done well is in creating hype among gamers before the game was released. They made the game multiplatform, then more gamers could play it. They made Genshin Impact free to play, and not heavy pay-to-win, closer to pay-to-fast mechanics. (like lots of other gacha videogames)
According to the characteristics of Genshin Impact, it can be concluded there’s no special reason to hate Genshin Impact particularly. Genshin Impact is like many other RPG games and gacha games. As I mentioned in first paragraph, the UEG’s hate to Genshin Impact can be more related to a lower previous exposure to action-JRPG and/or Gacha games, rather than hate against Genshin Impact systems and mechanics.