I know nothing about Porterville, but I wonder why you assume that because of his self-proclaimed ethnicity that he's not American but an immigrant? And, what responsibility is it of his (or hers - as I said, I don't know Porterville) to encourage other hispanics to learn English?
This confusion of ethnicity and nationality is the biggest problem I have with the illegal immigrant debate. In fact, I've been asked a few different times if I spoke English, just because some idiot assumed that my brown skin meant that I probably did not. There are concrete national and economic security reasons for wanting to control the borders; "heritage" is an emotional one and lessens the quality of the debate.
I am going under the assumption that his ancestors came to America, and that he is an American. It may not be his responsibility to encourage immigrant Hispanics to speak English, but it would be to everyone's advantage.
No one is saying that legal immigrants are unwelcome, but that when they do come to America, at least be part of America and speak the language.
Those of us who are also descendants of immigrants, or Native Americans, certainly understand. The sooner they become full-participation citizens, including speaking English, the sooner they will succeed. This is for their own benefit, not for those who don't want to hear their language. Drop the labels and become Americans!