Do you people take 40 minutes to read a line that's, like, 5 words long?
You glance, determine the words by their first 2 or 3 letters + context, and you fill out the rest in your brain, which takes about a fraction of a second.
Even less hard in animation, since there's really no risk of losing a nuance facial expression, by looking away from the center of the screen for a milli second.
I think I've watched hundreds of films with subtitles, both from the US (now I don't need them for English, but it wasn't always like this) and various movies from the rest of world, from Ukraine to Japan, to Thailand, or whgerever, and the subtitle reading was never a problem, because the more you do it, the faster you become and the more natural it gets.
On the other hand, watching dubbed films is just an atrocious experience, not just because of sound mixing and lip sync (which aren't as big of a problem in animation) but especially because dubbing is often done quicker and cheaper than the original VO, it usually doesn't have direct supervision of the creator, and I think the cadence and sound of a language are really important in defining a culture, even if you don't understand 100% of what's being said by ear.
And I am from Italy, a country that not only dubs 99% of the things that get in, but also can't shut up about it, and it's very proud of its "dubbing school" (which I admit, can get very good, when they put in time and effort), so you could say I was culturally conditioned to love dubbing, but fuck if I can't stand it, 99% of the time.
And I noticed every time I prefer it over the original, it's just some nostalgia thing, like Futurama or The Simpsons, I like them in Italian cause that's how I watched them as a kid, but I'd never dream of watching Rick & Morty dubbed.
Same for Ghost in the Shell and I think Cowboy Bebop has the same effect on some people.
But again, this isn't some weaboo thing about purity, I started watching things dubbed and transitioned on my own to subtitles, with American movies and various foreign movies (though American movies are also foreign movies to me, lol) because the difference was just massive.