looks like they were at fault, hamilton realised his error and moved over though it looks like
He shouldn't have been on the racing line, that was the problem.
But there was no other option than to punish them given the rule, as they did impede both drivers, intentional or not.
It's such a silly rule, (though easily rectified by enforcing that your slowing down lap should be within a % of your quickest lap) though I was under the impression that cruising back at such a slow speed after your hot lap had now been banned?