I think it's definitely related to KD, but I think it's good for him to show confidence/cockiness.
They still have to be beaten in the playoffs, and if LeBron can start playing with a mean streak, it's going to be over again this year. Let's be honest, he's the most physically athletic player probably ever, his tools are off the charts. The knock was only ever his mentality, not his intelligence, but his fierceness.
He's proven he's tough, but he's showing another side. He's saying "oh yeah, Durant is the best now? Watch this."
I think LeBron wins his 3rd this year, but that's me.