Considering I don't speak Japanese, it's presumptive to say the subtitled version holds truer to the original vocal performance.
Well, it is the original vocal performance, so I'm not sure what you mean here.
What we take to be the "original vocal performance" is actually our ears and brain decoding that performance to match the words on the screen. We hope that we're getting the inflection to match up, but it's really our take on that combination of sound and word, and not as pure and true as subtitle purists (dub snobs) like to believe.
I also don't know how that's unique to animated movies, but I assume you don't feel the same way about foreign-language live-action movies.
It's not, and twice now you've tried to apply my argument outside of Studio Ghibli, which is the debate on this table. I almost always watch foreign language films with subtitles, but while I have no argument for subtitling being better or worse than dubbing, when it comes to Studio Ghibli, I often select the dub. I find it to be as acceptable an alternative as any dub I know. You may see it as colorizing black and white films, but if that be the case, these are the best of that bunch to the point where I don't notice something is off and simply get lost in the film. I have more problems with dubbing in Leone's Dollars Trilogy, and those are often done by the actual actors.
every movie has infinite alternate versions, one for each person watching it.
And each version is a work of art unto itself. That is the argument of Copie Conforme/Certified Copy.