F1: Hamilton Escapes Penalty Despite Outrageous Weaving

The rules are quite clear in F1, a driver may change lines once in defence of their position, which beggars the question how did Lewis Hamilton escape penalty for what amounted to the most outrageous weaving I've seen since the 1980s?

At the very least a drive through penalty should have been imposed or in lieu of that a 20 second time penalty at the end of the race.

I'm amazed that no appeal has been lodged, especially by Ferrari who would see Felipe Massa increase his championship lead should Hamilton be demoted.