Al Jazeera have been struggling ever since they started their English channel to become available in the US. As you say, the channel has a very good reputation for its journalistic values, and is made up of people from all around the world, particularly many former BBC employees. Al Jazeera can be received throughout pretty much every country in the world—except for the States. It's a bit ridiculous. Although Google/YouTube have launched a partnership with them, and have in fact been providing a live stream for several years now.
Regarding the providers, I want to say that it's pretty insulting to the American people that they consider them so simple-minded that they'd be outraged against, or afraid of, something simply because it has a foreign-sounding name. On the other hand, some such tendencies can't be denied, like when you get into trouble if you want to travel to the States with a Middle Eastern name (as if an actual terrorist wouldn't be travelling as "Joe Smith"). Some such people are out there, and are quick to stir a shitstorm if their local provider actually does take up the channel (it's happened before). So some providers probably think that serving the few who'd be interested in the channel (actual news isn't as popular these days) wouldn't be worth the risk of riling up heaven knows how many lunatics.
Al Jazeera is my news channel of choice. I think BBC and CNN are okay as well in terms of objectivity and journalistic values, but what I like about AJ is that they cover all the corners of the world, not just "the West", where the money is. You know how people sometimes complain that our media doesn't care about war, hunger, poverty, child mortality in third-world countries etc. simply because they're too far away for us to care? AJ is pretty much the only channel out there that isn't like that, and tries to give a voice to the disenfranchised, to those we tend to conveniently forget. That they usually have local journalists report from their home countries, rather than sending over generic correspondents, is another nice touch. They're one of the few who still do actual, investigative journalism, and who risk their own safety to report from war zones (ever notice how in those situations, 99% of footage you see on any channel is courtesy of Al Jazeera?). Of course it's still a business and everything, but I find their idealism, which you can still feel in most of their reporters, very refreshing and beautiful.
As for the Arabic Al Jazeera and its reputation in the West, I don't think it is deserved either. All you hear in our parts is that they aired Bin Laden's tapes. What they didn't tell us is that they did so only after considering what parts to cut out, and always followed it up with a diverse and moderate discussion panel. They didn't "offer a mouthpiece to terrorists"—they reported the news, responsibly. Don't forget that Al Jazeera is considered one of the major forces of liberal reform in the Middle East, and behind the so-called Arab Spring. They revolutionised the local media landscape by providing independent journalism where before there were only state-controlled, dictator-mandated propaganda channels. They are to the Middle East now what BBC Radio was to occupied WWII Europe.
And finally, consider the fact that they were, or are, attacked vigorously from both sides. Rumsfeld called them an instrument of the terrorists, Al Qaeda called them a puppet of the American imperialists. I think that's a pretty fine sign that you're reporting on all sides of the issue.