If what I've read in a couple books about Armstrong is correct, his little speech/rant was something he had thought about for a long time - he just doesn't fly off the handle. Specifically, I think David Walsh and the contributors to his book (LA Confidential) were the main focus of the rant. Next, the French/European press might have been targeted. And finally, nitwits like LeMond and other back-biters in the ranks could have been his targets.
The thing about Armstrong is that his memory is long and his sense of justice is sometimes harsh (look what he did to Simeoni in the '04 TdF). He doesn't like people to get in his way, and there's a strong sense of righteousness in his actions. Plus, unlike LeMond, Hamilton, and some others, he is pretty brash - the American that Europeans love to hate.
I liked what he had to say.
Dean