I agree. But Kobayashi didn't do anything from either! He had the racing line. You can't expect them to go onto the grass or just slam the brakes just so that Hamilton can get the best line.
No, but you can expect from both drivers a certain level of awarness. In Kobayashis case, he deliberately followed Hamilton onto the right, using his tow to gain a speed advantage and then put himself into a gap that was closing. That gap wasn't closing quickly, it was closing at a steady rate, as Hamilton changed the angle well before. It was also Kobayashi that turned in a split-second before Hamilton did the same, and from pictures it's quite visible that there would have been enough room for both. It just didn't happen, by the smallest margin. In fact, at the moment of impact, Hamilton just started to turn in.
It was poor judgement of Kobayashi to 'risk' his own front-wing by putting himself into that position of possible contact given Hamilton may not see him - especially following his own words that he was never intending to overtake.
On the other hand, it was poor judgement of Hamilton to not realize that the Sauber was gaining on him despite the DRS advantage he had and that he should have left a bit more room.
I suspect the stewards agree with this, given their action was "racing incident". If it had been one drivers fault entirely, I suspect we would have seen a different action. At the end of this, I think one should also realize that from the vision of a helmet, the side mirrors don't always give you the full view, which is why I think if it hadn't been a Sauber but a Ferrari or a RedBull, he would have expected it and as such, it wouldn't have happened.
I don't want to start this argument again, but this season Hamilton has been in a lot of incidents. By now I think it happened too often to blame it all on others. I think Hamilton just needs to maybe watch out a little bit more and not just expect everybody to get out of his way. By now he should have realised that isn't going to happen.
I honestly don't believe that a driver, regardless how many incidents he may have been involved in (assuming racing incidents), should bear any relevancy to what action should be taken. It should be looked at as a per incident basis and the key factor is "intent". On that account, Hamilton had his fair share of bad luck and bad judgement. Per the rules, he has accounted for them one way or the other. In this particular case, he accepted that he was at fault, despite not showing any of the "get out of my way" mentality or frustrated driving. It wasn't an overambitious overtake either - just bad judgement of not leaving a bit more room.