on that note... if you are playing o!m maps that aren't o!m specific, you don't even have a right to post lol. the holds and releases make a lot more sense there than in the auto-generated beatmaps made by osu! itself.
Also, about the keyboard business, keyboards basically have no effect on o!m as long as they don't have serious problems with ghosting. Having mech keyboards mostly helps for stamina, which in rare cases are needed in o!m for the current maps that are out. Probably matters more with the more insane maps elsewhere, but right now o!m doesn't really have any around.
Lastly, I only brought standard up because there technically is a right way to play something, but other non-conventional methods do exist. The point here is that the hold notes are mapped to something, and the mapper used the hold slider so that it matches something in the music, and the player must abide to what the mapper wants. There are different ways to make it not as awkward and hard to release at the right time, but the mapper decides what he/she does. And anyway, you basically arguing with how a game works. Guitar hero has a very large hitbox for notes while rockband has a much smaller hitbox. If you don't like how rockband is so harsh, go play guitar hero. It's basically like that. If you seriously hate this release thing that much, you can try to find another game which does not have this or make your own. This isn't something that is objectively bad for a rhythm game.
Also imo, it adds an extra layer of depth to the game. And honestly, it's not that hard to release at the right time. You don't lose that much accuracy releasing at the wrong time.