Immigration Debate

I watched this video from MSNBC. It's about the growing Hispanic population in some small Iowa town. Supposedly this story has something to with the ongoing immigration debate in this country, but the connection is never really explained. Is MSNBC suggesting that the 3000 Hispanics living in this little town are illegal immigrants? If they aren't illegal, then how are they relevant to a debate on illegal immigration? People are discussing apples and MSNBC's contribution is a story on oranges? Does the mainstream media actually grasp the debate that they're trying to cover?