Stand alone video is not available as of this posting. However, if you skip ahead on this CSPAN video to 2:45:05, you can see for yourself how AG Holder came to the opinion that SB1070 was unconstitutional.
So when AG Holder was on Meet The Press saying that SB1070 "has the possibility of leading to racial profiling" he really did not know what he was talking about, because he had not read the law. When AG Holder called law's passage "unfortunate," and questioned whether the law was unconstitutional because it tried to assume powers that may be reserved for the federal government he really did not know what he was talking about because he hadn't read the law.
In the above video, Holder said that he was basing his comments on what he had heard from the media. So the top law enforcement officer in the U.S. is basing his opinions on law on what the media tells him? This makes me laugh, because for decades those of us on the right have heard that our opinions are not our own, but the opinions of Limbaugh, Hannity or Beck.