I think anyone who wants a decent job/education here, would be well advised to learn English. On the other hand, most of our forefathers did not come here knowing English, mine did as they were from UK, but most didn't.
That's because the English language is spoken by the majority of the United States and it makes sense for them to learn English as quickly as they can but to discriminate against them because they have not yet learned English is simply unacceptable. Almost every other country with a major English speaking population also finds that English is spoken frequently. The second language of most non-English speaking countries is English. You go to Germany as a tourist and they will speak English to you. If you go to Russia, China or anywhere else you will find that they will be able to speak English with you. They do so because they recognize that English is an useful language to speak. Of course they get upset when Americans come to their country and refuse to even try speaking their language and demand that they speak English to them, but this isn't what Spanish speakers are doing in this country. They are simply speaking their native language while trying to learn English at the same time. It shows the bigotry of those who get upset over this (i.e., it was true of every immigrant group and these people have decided to ignore history because it doesn't support their claim that these groups refuse to assimilate).
Problem with the flood we've had in the past 30 years, the immigrants do not feel compelled to learn the language, so much of their environment is Spanish friendly. That to me is not a good thing, not because they shouldn't have access to news and such, but because they can't rise socioeconomically. Keep the language at home and gatherings, but learn the language.
What you have to understand which I think you fail to understand is that every immigrant group was never truly successful at learning the language during the first generation and they preferred to speak their native tongue whenever possible. Almost every big city had areas where no English was spoken and there were entire towns where the street names were not even in English. This wasn't a bad thing. Now, in El Cenizo, Texas the City Council conducts its meetings in Spanish because they understand that the people of the city were predominately Spanish speaking. Some people may have a problem with this but the reality remains that it is only natural for them to do so.
On the other hand, I don't think a parent speaking to a child in native language in the store equates with not learning English. They could be here legally and just arrived. More likely, the child knows English fine, but parent is more comfortable with home language and wants the child to know both.
That's has been the case since this country was started and every immigrant group has spoken their native language during the first generation and the second generation are the ones who completely assimilate while retaining their cultural heritage. This is good for the country and for our society.