Yes. It doesn't detract from >me< the consumer but it takes away a whole layer of creativity from the artists
From a mere development perspective, balancing different difficulty levels take away time from the devs, improper balancing can create whack situations like lower difficulties being the actual hard modes, or easy spreadsheet methods that invariably makes "hard" a synonymous for tedium.
From a more important perspective for me, I think making games too hard for no reason, or too easy for no reason, takes away from the intended experience. Creative people craft different scenarios with certain emotions and reactions in mind and difficulty certainly plays a big role in that. "This guy is your rival it sure would be a bummer if you could one-shot him while underleveled", "this stretch in the game punishes your mistake very hard to drive point home how dire the situation is for the heroes", "this area is meant to be a huge skip if the player can deal with the difficulty spike".
If you can just lower the difficulty slider or give yourself god mode at those points at will, then what good was it all for?
I think our disagreement here is that you seem to see games as mere products; if they're too hard you can't consume them and therefore they've failed at their task, akin to a fast food meal that's too hot to eat immediately. I wholeheartedly disagree with this approach, just accept that hard games are hard and either improve or move on imo.