Although the statement "Flatten Palestine!" has NEVER been made by Israel or Jewish clerics (and hence rings completely false), statements such as ...
"Kill All The Jews"
"Destroy Isreal"
...are accepted and commonplace. Let's take a look at just some of these statements in 2013.
It will be wrong to say that all the Jewish clerics are Angels and all the Muslim clerics are demons. Israeli Rabbis, such as the late Meir David Kahane has made disparaging remarks against the Palestinians on several occasions. Even recently, another Israeli Rabbi suggested killing any non-Jew, including children and babies, who pose a threat to Israel.
http://www.thenational.ae/news/world/middle-east/israeli-rabbi-approves-murder-of-non-jews