My take: It would seem a triviality for Armstrong to concern himself with Evans' little lunge across the line. Evans wasn't going to gain time on the elite group he was coming in with, but it seems fair to suggest that he had the right to up the pace to gain a few seconds on Vino and the others for whom he is fighting for a top 10 GC placing. That being said, I suppose Armstrong probably felt a bit perplexed as to why Evans would decide to showboat like that considering Evans had been content to draft all the way into the finishing stretch.
And although this little incident has become fodder for the anti-Armstrong crowd, Armstrong himself has said nothing publicly about the incident (at least to my knowledge). Evans said Armstrong asked him "what was that for?" and characterized Armstrong as "******" at him. Perhaps, although from what I saw of Armstrong's demeanor after they finished that day, and the fact that he didn't find it necessary to comment on the incident, seems like Evans is the one who has overdramatized Armstrong's reaction (just as Evans overdramatized the finish itself . . . hmmmmmm).
As an aside, there has certainly been a lot of discussion about rider etiquette since Hincapie outfoxed Pereiro last weekend. Seems like every day there's another wrinkle to the issue of when it's OK to "suck wheel" and when it is not. Apparently, since I see that there is a lot of support for Evans latching on to the back of Armstrong's wheel to move up in the top 10 on GC, I will presume that those same people no longer have an issue with Hincapie trying to move into the top 20 by doing the same thing . . .
Or maybe the answer is even simpler than that -- you "wheelsucker" snobs may simply have a rather glorified idea of what riders should be doing in pursuit of a successful finish. In virtually every case, wheelsucking is only frowned upon by the guy who is disadvantaged by the maneuver. The other guy and his supporters will always be able to find a reason to suggest it was permissible.