I don't blame you for getting pissed and I am hispanic. I remember at my first job, I was the only hispanic who spoke engish and I was the translator for the other ones ( they were hard worker people who were doing their best to understand and I just translated if there was any kind of misuderstanding). However,the supervisor always pissed me off, he liked to always change the radio station to an 80's classic rock station. I love classic rock, but having to listen to the same freaking song everyday was a nightmare. So I got my mp3 player and asked my other spanish colleagues for some salsa and other spanish music and used my FM transmitter to block his station. One day, he came and we were listening to Celia Cruz. He got so pissed off , he thought it was the radio. It was priceless. We still do that from time to time, just to get a reaction out of him.
I do think that people who move to US should learn english, but mostly because it would benefit them tremedously. One of the people in the company I mentioned before had so much knowledge about the job and so much experience that if he would have known english , he probably would have been the supervisor. I told him that he should learn english as soon as he could because he was young (32 years old). Hopefully, he did take my advice.
Regards
ng