There are a number of reasons for those statements, but really the core of it has to do with what you think the role of fansubs is supposed to be for anime communities. I tend to consider them a last resort, rather than a first. The first fansubbed anime I ever seriously picked up was Magical Girl Lyrical Nanoha StrikerS, because I didn't see any other way of getting access to the series. Heaven knows it didn't have an American release back when I got it. (It still doesn't, as of the time I'm writing this.)
This is because I think that fansubs are rightly supposed to be a patch. There was (and still is in some ways) a gap between the interest in anime in the United States and the availability of anime in the United States. In Japan, new anime comes out every season, airing every week. Whereas the United States got a fraction of those shows, and even then would often see sanitized, altered, or just plain bad versions. Anyone up for Cardcaptors? No? Didn't think so.
In such an environment, it comes as little surprise that people would get together and put up subtitled versions themselves, providing the anime that people in the United States wanted to watch. It's probably not legal, given that that's distributing the anime without the rights to do so, but the company isn't actually losing anything, because if there's no fansub people simply can't watch the anime. And hey, you know, maybe someday we'll get a proper DVD release and can buy that when it comes out, right? (I seriously doubt that most fans actually do buy the anime they've already watched, but maybe I'm wrong.)
These days, that's changing. It's changing for me on a personal level and it's changing for the entire U.S. anime community on a societal level.
For me, well... I'm studying Japanese. I've been to Japan once and want to go back. I went out and bought anime DVDs left and right while I was there. I don't need, nor do I want, a patch anymore: I want to watch the anime on TV as it comes out, and then buy the Japanese DVDs once they're released. Aside from the myriad of special features on those DVDs, there's the added bonus that I don't have to worry about whether what I'm doing is legal or moral. Because it unquestionably is. And if you take Nanoha StrikerS as an example, well, I have all of those DVDs, and still think that every single cent I spent on those was absolutely worth it.
On the societal level? Well, go look at Hulu one of these days. Go back and look at my earlier post about Fate/Zero. There's anime out there already. Some of it brand new from Japan, in the latter case. That patch that fansubs are supposed to provide, filling the gap between what U.S. fans want and what they have? We're seeing companies moving to fill that gap themselves. They're exercising their right to distribute their anime in the fashion that they prefer, even in the U.S. market.
The role of fansubs is to fill a gap in the U.S. market. If this trend persists, if more companies and studios decide to step in themselves, that gap might not exist in the near future. And then we stop talking about role, and start talking about duty: the duty of fansubs and their creators to recognize that without a legitimate role, fansubs simply should not exist.