I am not sure I can really fault Butler for this if he's dealing with effort issues on his current team. When he was traded to Minny, he was probably licking his chops - you've got a potential all-time big and a cagey athletic freak that is capable of doing the dirty work on D but they've underperformed.
We all bitched about how Irving's wavering effort levels - he never put effort into his defense, he should work on his body more in the off-season to prevent injuries.
Butler is cut from an old-school cloth and has worked his tail off to get where he is now. He is looking his last prime years straight in the eye and wants to compete for championships.
Could he have positioned his desires better? Hell yeah but he's human. However, if a colleague was letting me down strictly due to effort and focus and it was hindering my career aspirations, I would make an issue out of it as well.
The only problem is I really don't know what team is a good fit for him, from a contention standpoint. OKC makes the most sense to me but you're still dealing with usage problems and I have no idea what their cap situation looks like.