Completely unprofessional from Kane.
When you sign these new contracts on eye watering amounts I think you have to be prepared to act properly at all times. If you start throwing the toys out there is just no excuse in my eyes.
You can't on the one hand leverage your power as a key player into extortionate wages and then simultaneously expect the club to want to sell you. The reason they gave that contract to Kane was to show his value and protect their own investment in him, both are pretty obviously key reasons that he would be an unlikely sale. You sign that with your eyes wide open, I wouldn't trust any gentleman's agreement in modern football, I'd only trust the bit of paper being signed.
The reality is that if the eventuality Kane wanted to bring about was his future sale, he should have never have signed a contract. That means taking a slight risk on his own form and fitness, accepting lesser wages for a period - eventually Levy would sell, or at least the chance is large. But no he expects to win on all ends and some people think that is correct behaviour.