A major theme was racial profiling in arrests and traffic stops, as if white people don't get stopped for not wearing seatbelts. The piling on was thick. I can understand why Sheriff Arpaio's deputies were furious (see the video which is briefly excerpt in the clip below). No one from his office was invited, yet his policies of lawful immigration enforcement came in for a bruising.
Since the Democrats are in the majority in the House, they get to set the agenda and choose 3 out of every 4 hearing panelists. While there are elected Democrats who favor immigration enforcement (like Heath Shuler and Jon Tester) but the Immigration Subcommittee does not have any Dems like those virtuous ones.