So, it's plain that many people want kill on sight enemies because they just want to fight things. The problem, IMO, is that D&D put too much depth into its kill on sight enemies as opposed to things like video games (I'll admit, when I first got into D&D in 2007 I was surprised by the sheer number of monsters with human-level intelligence; partially because I never cared for Lord of the Rings and underestimated its impact, I guess).
When I played the JRPG Breath of Fire 3, for example, every now and then a clearly intelligent enemy would show up in encounters in an area (armor and weapon using orcs were one of those). No matter how many orcs (or whatever other intelligent monster you found) you fought in combat in a dungeon, you'd never see an orc outside combat or any sign of their existence as inhabitants living in the dungeon. They effectively popped into existence as battle started and were returned to non-existence if you ran away.
Legend of Zelda: Breath of the Wild goes a bit farther in establishing intelligent monsters as actually inhabiting the world with campsites and fortifications, but they're still there to be killed on sight (and believe me, that game gives you lots and lots of tools for fun ambushes, such as parasailing from a cliff and dropping down towards the center of a camp while firing exploding arrows in slow motion before the resting monsters can even get up and grab their spears). There are no monsters you can talk to, baby monsters, monster villages, etc. Arguably these creatures are more akin to D&D fiends because they burst into smoke when slain and are spawned full adults, but personally I view the former as Nintendo not wanting their childrens' game to leave monster corpses laying all over the place and the latter as a gameplay conceit to justify previously-cleared areas suddenly being repopulated by enemies rather than being empty for the rest of the game.
Basically, D&D early on made the mistake of not making the vast majority of monsters either unintelligent beasts or intelligent fiends that don't reproduce naturally. Instead they just said "these guys are Always Evil and therefore you're a bad person if you DON'T kill them"!
Going back to video games, I'm not particularly inclined to believe the game designers of Legend of Zelda: Breath of the Wild were concerned about the morality of killing Always Evil intelligent monsters or how that could be interpreted. I think they did what they did because the vast majority of video games let you inflict violence against enemies without worrying about the ethics of it ("Is Mario killing goombas when he stomps on them? Who cares!"). Games that worry about the ethics of violence are adult entertainment whereas games for kids/ adults that aren't interested in games that force them to examine the ethics of violence sanitize violence as much as they need to in order to keep their audience from feeling uncomfortable.
Hell, the biggest multimedia franchise in history (that has earned $92,000,000,000 in revenue), Pokémon, is aimed for children but is explicitly about capturing wild animals and forcing them to fight each other with attacks that should be incredibly deadly, including OHKO moves with names like Guillotine. It's okay, though, because Pokémon just so happen to LOVE being taken from their natural habitats and fighting each other, they can't die in battle and merely faint (which has no long-term detrimental effects on a Pokémon), and the entry in the series where people in-setting start asking each other "hey, what if this is actually all totally naughty word-up?" (2010's Black Version and White Version) reveals that the people who started spreading these concerns are part of an evil organization whose leader wants to trick everyone else into releasing all their Pokémon back into the wild so that they can be the only people with super-powered monsters and use them to conquer the world.
I'm honestly very curious if a sincere effort by D&D to acknowledge unfortunate implications and problematic aspects in the game would spread to affect all manner of games that utilize violence.
