When people talk about this issue in a vacuum, sure, it sounds weird because why shouldn't what's okay for one country be okay for another? We were all against the Xenosaga content censorship, right?
The problem is that this isn't actually a situation that arises in a vacuum. It used to be that there was plenty of trashy, pervy stuff in Japanese games, but it was in games that made sense -- from softcore T&A sims like DoAX or Onechanbara all the way to hardcore H-games -- while other stuff was, by and large, actually appropriate to whatever type of theme and genre they represent.
Over time (the last decade or so, especially) a combination of cultural and economic factors (the ultra-low birthrate, the relative unacceptability of gaming as an adult hobby, etc.) have combined to make the financial sustainability of games made primarily for the Japanese market very precarious. The result has been a well-documented effect where, with general audience purchases dwindling, publishers have decided to go after people who will actually spend a lot of money by aggressively targeting the pervert otaku market with every game, regardless of what any other part of its setup would suggest.
Over here in the US, videogames are very much a general market product for all ages, and people have a strong expectation that the content in a game will match its external presentation, the exact same way they'd expect in a movie. Much like people who might enjoy an R-rated erotic thriller could still get upset at a random, incongruous strip show in the middle of a PG or PG-13 fantasy adventure movie, people who might have no problem with explicitly erotic games or contextualized mature content might still be turned off by jokily outrageous fetish imagery in what's supposed to be a serious story, or random sexual minigames in a previously conservative and restrained tactical RPG series, or having to beat magical women and choke them with dog collars or whatever just to explore a dungeon. If people see this kind of incongruous thing, some of them are maybe going to say "fuck this" and stay away from the game, or the series, or the publisher.
Because Nintendo doesn't need a specific ultra-niche community of big-spending perverts just to have a successful game launch here like apparently everyone does in Japan now, and because losing audience members because of a distaste for random fetish pandering isn't really conducive to their brand goals, it only makes sense for NOA to cut as much of this stuff as they can out and try to have a product that at least vaguely targets an audience of normal people.