Hamilton claimed responsibility for the shunt with Albon as soon as he got out of the car. As soon as he publicly accepted responsibility, they just had to say "what punishment do we give him?" A matter of moments, if they had wanted to do it.
But these events are very structured and maybe there was something else going on at that moment that prevented the stewards doing that quick-response action.
A shame for Sainz not to get on the podium but at least him and his team got the correct points in the end.