Nobody said any other country was more magnanimous than the United States when it came to illegal immigration. In point of fact, OSC actually said that in acting this way, the USA had become just like every other country. Nobody said that Mexico was better than us, but why should we endeavor to lower ourselves to the standards of other countries? Should that be the motto of the country? See who's getting by out there, aim low and be just like them?
The reason that it seems racist to want wholesale expulsion of illegal immigrants is because the surface and stated rationale for wanting this doesn't make a lick of sense. Most of it's baloney. Mexicans aren't all pedophiles and lepers. The US economy would in all likelihood suffer horribly, not benefit, from the expulsion of all illegals so the jobs/economy/taxes argument is bogus. The arguments that aren't baloney are all suspiciously targeted. There's a huge public outcry against Hispanic "slave workers" in American agriculture... and this is awful and something should be done... but it's only an issue because hating on brown people has become a hot-button topic. Nobody talks about or gives a shit about Koreans illegally being funneled into the country to work as sex slaves.
I live with a case study in conservative paranoia called my father. Every time we talk about this issue he starts with the crap he heard on the radio that day, "they're taking our jobs," "they're all criminals," etc. but within a couple minutes I can always back him into a logical corner and get him to admit that really, he doesn't care about any of these issues as much as he cares that he's frustrated the person at the drive-thru window at Wendy's speaks with a heavy latin accent and has trouble understanding his order. He has a certain idea about how the country should be, formed by growing up in Ohio in the 1950s, and doesn't want to have to change his idea. He likes people who look like him and sound like him and speak the same language.
What it boils down to is that these ethnic cleansing bills, though they play well among racists and turn out lots of voters, they usually do far more harm than good if they pass. When I see Irish-Americans or African-Americans or, for that matter, any American that's not Native standing up and calling for the prosecution of these "illegals" it's impossible not to see them as huge hypocrites.
There are problems in the country, granted. and some of those problems stem from immigration. The intelligent solution, though, is not the draconian enforcement of existing laws. That does not reflect the reality of what the country has become, and believing this is the solution or that the country can go back to how it was in 1950 is itself a fantasy. The law as written needs to be changed.