Lewis would have had the racing line, if Webber wasn't there, but he was. And because he was there and he was there on the left side in a left hand corner the space belonged to him. And he was on the kerb with half of the car, because Lewis thought, Webber would step back because of his tyres, but Webber was confident of his tyres.
Ergo racing incident.
Lewis should have known that Webber was confident enough not to let pass the golden opportunity to win the WDC.
My two cents.