Hamilton was using DRS, but even with it, he didn't have any more top speed than Kobayashi (though he got to top speed quicker, hence the pass). Nor did he have more top speed than the Mercedes cars.
Hamilton knew he didn't have great top speed. And he would have seen Kobayashi tucking i and pulling out - no opaque water spray here. So he has no excuse, and it was good to hear him admit that he was 100% at fault, just like he was in Canada.