Most likely because many English voice dubs tend to have bad acting. People just don't know how to do it right, and it results in nothing but a bad-quality voiceover. Some people don't care, and some people would rather not risk it. I'm sure there are other reasons as well.
But in the end there is no reason to point out people who prefer subs, and people who prefer dubs, and call the other 'stupid'. Just because you prefer dubs doesn't mean you should insult all subs and their fans, and vice versa. The whole argument is pointless.
I don't mind dubs, actually prefer some over sub. My guess is as good as yours. Some wanna be like "The original is always better" Others may just not like the quality of acting, which is sometimes understandable. An example of bad dubs would be Karin and Higurashi. Both of them have cringeworthy dubs. Then as for me, Fullmetal Alchemist and Ouran HSHC are, to me, better when dubbed. That's just my opinion. I think it's the pangkalahatang quality though.
I can't speak for anyone else, but the reason I don't like dubbed anime is because everything sounds too awkward and forced with English voice actors. I like subs because the voices actually sound natural, and I'm quite a fast reader so subtitles don't bother me at all. In fact, I actually prefer to have subtitles when I'm watching something, even if it's already in English.
I like sub's just because I like it. I really don't mind dubs. But If I had to choose it would be sub. I guess I just like it better I like the Japanese LA. If I had to watch it in dub I surely wouldn't mind it. No probs.
#1 Because they don't like their acting. #2 Because they don't want to wait for the English version. #3 Because they like pagbaba the subtitles. #4 Because the first is the best. #5 Because we all like different types of anime .
Could be for the reason that Eng dubs overuses the same voice actors, and some of the voice pagganap is considered bad. It's deemed worse than subs most likely because English speakers can actually tell when the pagganap is bad as opposed to when it's in a language you don't really know.