Considering he expanded his championship lead at the end of the day, you could still easily argue that he's effectively escaped meaningful penalty on the track. Had Hamilton gone on to win it would have looked more significant, yes. I won't say he's been "rewarded" for this shitty aggression since Vettel obviously has no control over Hamilton's neck restraint, but when points are the only thing that matters at the end of the day he still received a net benefit from the race, which is freaking absurd.
Anyone not in the championship battle would have been DQ'd, or at minimum punished further by the FIA. They just don't want to look like they're playing favorites, which makes them cowards. For precedent on how anyone else would be screwed, RoGro caused a wreck at Spa in 2012 that he received a race ban for, with the justification given explicitly mentioning the impact it had on the championship. Wrecking any random people further down the order? Meh. Contenders wrecking one another? Meh. Outsiders sticking their noses into the battle at the front? Punishment!
Edit: Wanted to add that I really hope this doesn't spark a new run of epic Ferrari favoritism and entitlement out of the FIA (hi 2010). They haven't been contenders for years so we haven't seen how much weight they'll throw around. With a sample size of 1 incident it's obviously impossible to draw any conclusions.
