A lot of anime fans (the vast majority, even) got into it through Naruto fansubs, and I'm sure a lot of people in this thread fall into that category. You guys have never heard the horrible dubs of the 90s, and thus you don't see how quickly the dub voice talent has been improving. You also aren't native Japanese speakers, so you can't tell if their acting is good or not. Look at Soul Eater. 2ch is RAAAAAGING over Maka's VA, meanwhile 4chan is fapping and cumming enough buckets to make it rain in Tokyo. Japanese VAs have always taken themselves seriously and continue to do so, whereas dub VAs are only starting to take their work seriously fairly recently, and it shows.
If you think the dubs you see on Adult Swim are bad, I challenge you to watch the first Akira dub, or the YYH movie dub without raging. Hard mode? Without laughing. Nightmare mode? Without cracking a smile or raging.
tl;dr: Newfags, you're making this anime_expert RAAAAGE.