Froome connected rather well with that guy, and at first I thought it was a little over the top-no pun intended!-but a bit later they went back and showed from a better angle how the flag the spectator had had nearly gotten caught in Froome's front wheel, and it did catch a bit on his left hood and pulled him off course for a moment. Could have been bad if he went down. Nicely done, Froomey.

Edit: The other thing about Froome punching the spectator is that if he had pushed the guy it seems far more likely that he could have gone down, even though it looked extreme to some, by punching him he stays safer.

As for the fan who stepped in front of George Bennett, wow he really got clobbered-went down hard and didn't move much after that. In the same way that it's hard to gauge speed when watching on TV, it was obvious Bennett was going much faster than it appeared, until he hit the guy.
Here's the clip in case you missed it: