Le Blaireau's path was blocked though (as was the route of the whole race, tbh), which is slightly different - short of RichP's hypothesised tripping (and how is Mr Armstrong's pushing him over going to mitigate that danger?) the "Liveclean" devil wouldn't have got into, and wasn't in the path of the race so far as the available video and photos show.
I wouldn't necessarily disagree with richp, although this guy is the only one to have been assaulted (there's at least one other sideline sprinter at the ATOC, the guy in the longhorn hat and "Texas" shirt) as far as I know. I've not seen any of the peloton exchanging blows with the flag wavers on the cols either (quite a few of whom seem to dart out of the path of the riders at the last second).
Edit: My bad, looking at Mondo's post, I can recall some water bottle squirting.