But, I have never heard so many people talk about dubs like they're perfectly acceptable, and not at all shameful or seppuku-inducing.
Maybe it's because I was way into anime in the 90s, and back then dubs were atrocious (I still largely think they are).
Maybe... most people felt that dubs have improved considerably since the 90s?
If you want an actual answer to the possibly-rhetorical question in the topic, I'd say around 2003 or 2004. That's about when dubbed anime on TV shifted away from exclusively mass-market long-running shows like Sailor Moon, YYH, Cardcaptors, and DBZ. Instead, better dubs like Cowboy Bebop, Wolf's Rain, Trigun, Texhnolyze, Read or Die, Witch Hunter Robin, FLCL, and Scryed (yes it's cheesy, but no more so than the show) were reaching TV audiences. And the consensus on more dub-centric sites is that other companies like ADV, Geneon, and Funimation had gotten their acts together and improved dub quality by that point as well.
But, especially after watching anime for the last twenty years, I have come to understand that the cadence, the verbiage and the aesthetics of the Japanese language factor very heavily into anime, even if you can't understand exactly what they're saying.
You mean the way that Japanese voice actors record their lines over storyboards and rough-cut animation, and the lip flaps are sometimes wildly off-sync?
But, I mean, if you look at the culture surrounding high-quality Japanese VOs, and the best English dub ever done, they're still miles apart.
If you go to major conventions in the US, you'll find plenty of fan following and attention surrounding popular dub VAs. The fandom has changed, and many of the teens/early-20somethings just don't associate English dubs with the stigma they acquired in the 1990s and before.
All the sounds that fall away, the puns and just jokes in general which aren't translatable.
It's not like every single Japanese pun and joke is the epitome of great comedy, and every dubbed/translated joke is automatically terrible just because it didn't come first. If you learn Japanese and see a lot of anime, the lameness and repetitiveness of Japanese comedy (and Japanese scriptwriting in general, hampered by the comparatively low lexical diversity of their language) really become apparent. I'd much rather have creatively rewritten English jokes than suffer through another round of "futon ga futonda" or "do bananas count as snacks?" again.
I feel like the larger acceptance of dubs over subs, and thinking that they're mostly equivalent is kind of like... a cardinal sin.
Then forgive me Father, for I have sinned. While I definitely acknowledge and refuse to watch certain bad dubs, most of the time, I just view the dubbed versions as the same show in another language. I still like subs better in general, but being worse than something else doesn't automatically make something bad.