From what I've heard today, the lies that MacNamee told were to the press, not a grand jury, not Congress, and not under oath.
Do you really think that if a reporter from the NY Daily News came up to anyone in the Yankee organization 5 years ago and asked them if they knew anyone on the team that was taking steroids that they would have been truthful?
The parts that I watched today showed me a calm MacNamee and a very jittery Clemens.
When you tell the truth you tend to look calmer and when you lie you tend to look jittery.