well that's something designers do. they use art to make the whole work on a functional level. i think what people may consider good music or a good story is subjective but the type of music or the type of story can be really off-putting if it doesn't fit the general work of the design.
it's a stretch to suggest this was some kind of nefarious deed. they wanted a better product for their region and they put in the work they thought would make that happen. how many kids in 1992 were anticipating the music of the japanese or european sonic cd they would have had to have imported? sega sold a product to consumers and then they bought it. it wasn't some weird bait and switch.
the argument reminds me of comments regarding '''''''censorship''''''' so pardon if i'm taking this more seriously than i should.
There's nothing to pardon. I also want to take this to serious territory (and I'm grateful for us being able to handle it in a civil way). Although I don't know which are those "censorship" comments that you refer to.
From your response I'd say you see videogames more as a functional product than an art creation. You see its art contents as tools for a functional design. It's respectable but I don't share it. And I also think it's too subjective, because what is that function exactly?
I accept such reasoning about things like, for example, brand logotypes, because the intended functionality is much clearer there. I can affirm the Apple logo works better than the Starbucks logo because it's demonstrated that more people is able to remember its shape (as it's simpler and relates to a known object in the real world), and it's more versatile to reproduce in mediums of all sizes, resolutions and color depths. And that's independent of how we like them aesthetically or as "art" creations.
But what are those objectives for a videogame? Transmit "feelings"? Tell a story? Be "fun"? Those are really subjective. I surely get a clearer message and a more exciting experience with the original soundtrack of Sonic CD, and other people do with the US one, but all of that is subjective.
The only objective function I can think of for a videogame is sales numbers. I understand Sega might have thought a Sonic CD with a different soundtrack more akin to the US trends of that time could sell more, and that's well intented from their point of view of an industry that seeks benefit. But what I defend is that we, as videogame enthusiasts that I think appreciate the medium rather than being shareholders wanting to maximize profits, shouldn't let that pass, and instead should pressure companies to respect the original works of creators.
In other words, I would respect the US soundtrack of Sonic CD much more if it had been commanded and made by the original team. And even more if Sega had enabled some way to get the original product as well (although I understand that's much easier now than then).