From this:

About a thousand protesters descended on a small town in northeastern Iowa [Postville] on Sunday, decrying the raid of a meatpacking plant [Agriprocessors] that arrested nearly 400 residents and calling for a change in federal immigration policies...

Sunday's protesters — many arriving by bus from the Twin Cities and Chicago — circled the streets of Postville on a route about a mile long. Some clutched banners and signs such as one that read, "United for immigrant and worker rights."

The alleged abuses at the plant would not have occured without illegal immigration, something that many of those on the left rush to support. But, wait, there's more:

Getzel Rubashkin, an Agriprocessors employee and a member of the family that owns it, approached reporters outside of the plant as the rally moved on. He said it was unfair to blame his family and Agriprocessors for the raid and suggested that unspecified competitors and enemies of the plant were behind the enforcement action.

UPDATE: There's video of some of his statements to reporters here.

UPDATE 2: There's a video on the march here; I didn't watch it but I'd imagine it's from the "liberal" perspective. There are pictures here and here.

UPDATE 3: Julia Preston of the New York Times offers "Iowa Rally Protests Raid and Conditions at Plant". She doesn't point out that those protesting in favor of illegal immigration are in effect helping those who'd abuse their workers. She says that FAIR "opposes illegal immigrants and proposals to give them legal status", implying that they have personal animus against illegal aliens. After a long discussion of the kosher certification-related issues, she brings on Getzel Rubashkin. Saying he's only speaking for himself, he says among other things:

"The high number of illegal people who were working here is more a testimony to the quality of their deceit, of their papers... Obviously some of the people here were presenting false documents... Immigration authorities somehow picked it up and they did what they are supposed to do, they came and picked them up. God bless them for it."