Israel has only done what was needed
As the writer suggests, go to the Google map of Israel in 1947. But you should know the U.N., while establishing Israel's independence, drew up that map. At one point, Israel was only six miles wide, not very defensible. At that time five Arab nations with a total population of 40 million, with modern armies, with modern air forces and the assurance that they could push the Jews into the sea. In comparison, the Israeli's population at the most was 1 million, a rag-tag army without any heavy armament, and an air force of three Cessna-type aircraft.
So sure were the Arab countries that they were going to win the war in short time that they invited their brethren out of Israel. Israel survived. What's more, Israel survived the five or so additional wars the Arab countries started against it. As a result of those wars, Israel gained territory from the losing Arab countries. An example, where Israel needed to keep the captured territory for security, was is the Golan Heights where Syria was lobbing artillery shells into Israel. (Israel, when overcoming the artillery positions, captured five Soviet army advisers to the Syrian army.) In another war started by Egypt, Israel bottled up the Egyptian army on an island and was about 150 miles on its way to take Cairo. Intervention politically by the United States prevented a gross humiliating Egyptian defeat.
Just look at the misery going on in other countries in the region. People are persecuted and murdered over different religious beliefs; there is a lack of democracy and citizens are at the mercy of their military.
On the other hand, Israel is the most stable country in the region where: democracy flourishes, all religions flourish, where science and health resources flourish, where its military protects its citizens (not the other way under Hamas control).
I suggest the letter writer read history, rather than lean on mucky propaganda.