"When in Rome, do as the Romans do."
When visiting a foreign land, follow the customs of those who live in it. It can also mean that when you are in an unfamiliar situation, you should follow the lead of those who know the ropes.
I think what part of the problem is, is that there's no longer the expectation, for whatever reason, that those who speak Spanish are expected to blend into America, which is an English-speaking country. The mind-set has changed from a melting pot, where immigrants learn to be Americans (collective) rather than retain most everything about the country from which they came and learn how to blend in to the American culture--assimilate--but still retaining their culture at home, etc. Don't think that this hasn't caused resentment in areas, especially those closest to the southern borders.
Not just Spanish - when I first moved to California, I went to the local DMV to pick up a booklet so I could study up on the rules of the road before taking a test for my new driver's license. Well, guess what. They didn't have a single booklet in English. Not one. All out. They had Spanish, Korean, Vietnamese, Chinese (I have no idea which dialects, or how many) but none in English. I was furious. My tax dollars at work. I had to call the DMV in Sacramento and have them mail one to me.
As you said, no need to learn English, we'll accommodate ya.
It's not rational to expect others to assimilate when they have no right to be here in the first place. Sorry, but you can't use imminent deportation as an excuse to lambast those who do not assimilate.