> The displacement is due to Israel's warning to civilians to leave the area of fighting for their protection

Most modern instances of ethnic cleansing are justified as military necessities.

E.g.: Armenian genocide

“Article 1—During war time, army and corp commanders and their deputies and commanders of fortified posts are obliged to destroy any assault or resistance and violently restore order with military forces in the case of opposition, armed attacks or resistance directed against the government orders, the defense of homeland and the preservation of public order.

Article 2—Army, independent corp and division commanders are allowed to transfer and relocate the village and town population in matters related to the military affair or if they feel there is an activity of espionage and treason.”

https://en.wikipedia.org/wiki/Temporary_Law_of_Deportation

You can't have it both ways though. If Israel fires back at Hezbollah and civilians are killed then it is committing war crimes and if it asks the civilians to leave then it is committing war crimes. In previous wars in Lebanon civilians were asked to leave and then eventually returned and so there are numerous similar examples where Israel's instructions and the situation was similar and there was no ethnic cleansing.