For the record, I do think it's important for immigrants to learn English. As someone who's taken the time to learn other languages, I think you have to be at least somewhat apathetic to not take the time yourself to learn the language of the country you're moving into.
There are immigrants in the U.S. who shut themselves up in their communities and don't make an effort to learn English. I've met a lot of them. There's also immigrants who make only the most minor attempt to learn English and give up.
But I also think they're a minority. English is actually a particularly hard language to learn. There's a perception that it's easy because we don't have gender or case, but the generational mishmash we have going on instead has actually made us a damned complicated case... BUT, I don't know. Part of me wants to say it's too much to ask to expect most of them to get past a B1/B2 level; part of me recognizes they're literally surrounded by English media and English speakers with a level of immersion that many language learners can only dream of.
BUT... Americans do need to cut some slack. Especially the monolinguals. Learning a language is damned hard work. The best most people here do is a few required semesters of Spanish/French that leave them barely equipped to order a cup of tea somewhere.