Hamilton was behind. Way behind and Button was allowed to block the overtake. Hamilton saw it happening, kept pushing instead of giving in and eventually hit Button's rear tire. Hamilton to blame.
Was it just me or after the collision did you see Hamilton try a ''kamikaze'' move to Button? I also don't see why he kept on racing and parked his car in a bad place when he had opportunities to park it well without causing SC.
The way I see it is Hamilton was CLEARLY faster than Button at that stage. Button simply wasn't expecting Hamilton to try to go around the outside especially Button was on the normal line, and the fact that Button couldn't see out of his mirrors wasn't helping either. Hamilton was way too far behind to try and drive out the outside. If he was half a car length further up, then Button would be at fault. But Hamilton was too far back.
Obviously I am not Hamilton, but if I was him I would have stayed on Button's tail and nail Button into the inside of T1.
IMO Hamilton is too agressive when it comes to overtaking. You need to know when and where to overtake. You can't just stick your nose up next to someone and expect someone to jump out of the way.