And lets be honest, what Massa did was way worse than what Hamilton did yet both get a similar penalty
Hamilton - tanked way too far into the braking zone for T1 after getting a poor start. Pulled into the path of his own team mate, panic-braked so hard that he ruined his tyres (presumably what sent him off the road just a little further round the lap), went sailing off to the outside of the track and caused a small amount of chaos.
Massa - went into the chicane too deep, tried to hang on to it rather than take the escape road and lose ground. Ended up in a position where hitting Hamilton was almost inevitable, did so.
I wouldn't have said "way worse", but definitely worse since he actually made real contact with Hamilton. But what can you do? Options are a 10 sec penalty or a drive-through. Was it really 10 sec penalty material?
Now, if they had several different variations - drive-through, stop-go, 5 seconds, 10 seconds, entire lap, then grid penalties for the next race if the incident comes too late in the afternoon - then you could make the punishments actually fit the crime.