It's only unfair if the club received an offer which was fair to his value. The reality is he was a player with 3 years left who grabbed both the golden boot and top playmaker award, is a big English homegrown talent, and City only have Jesus. The club had every right to pursue a fair fee.
If, as reports state, they only offered 75m+ add ons, then turning it down was correct. You can't pay 100 million for Grealish who wasn't even a starter for England and hasn't been half as good as Kane over the years, and then expect Spurs to not want more for Kane. Especially when Villa would have rejected that 100 if it wasn't a release clause.
We should certainly have been open to him leaving the club. Kane was well compensated with big wages and signed the contract by his own free will, he isn't a prisoner. Now if Levy received big offers but wasn't negotiating, that's on him. But we don't know that. No confirmed reports of a fair City bid were reported at all.