He jumped ship because he was being undermined, he wanted his own coach, which they didn't want to do and then ended up firing him anyway!
It seems like an excuse to me. It was widely acknowledged in the media that Walton was going to be fired at the end of the season, regardless of what happened with the Lakers.
In the end, he clearly wasn't committed to putting in the time necessary to do the job. Even if everything he said about Pelinka is true, show some professionalism on the way out. Tell Pelinka, Jeannie Buss, LeBron, just someone that you are stepping down, rather than getting in front of the cameras and dropping a bomb. Bill Simmons mentioned on his podcast a few months ago that he did the same thing at ESPN i.e. wasn't a hard worker, then randomly quit one day. He can point fingers at Pelinka as much as he would like, which could certainly be warranted, but he hasn't covered himself in glory with this whole situation. The irony of it is he pointed fingers at everyone during that interview today. Take some responsiblity for what happened and move.