I still don't understand why there's an issue since the land was bought. There may be problems with the zionist intention. But this just seems to me like a "good deal gone bad".
No, the Zionists aimed to acquire the majority of the land by buying it from the landholders but failed to reach their aim when the mandate was formed. The land bought was still under 8% of the total which would indicate that 92% of the original land mass belonged to the Palestinians.
Israel offered an arab state and it was rejected. Since then Israel has rejected a two-state solution.
Israel has never offered the Palestinians a viable state, in fact, Palestinians are working towards the acquisition of their own state, hence the two-state resolution which is the best solution thus far.
Regards