To accept compulsory population transfer in principle would set a dangerous precedent for international relations, and many nations would use such an excuse to cleanse themselves from "unwanted minorities". In other words, if it is accepted in principle that one can transfer and dispossess the Palestinian people so that Jews can have a "Jewish state," then
Why would it be unacceptable to "transfer" 10 million Mexican Americans to Mexico? or
To "transfer" a million Kosovan Albanians to Albania?, or
Even to "transfer" 6 million American Jews to the "Jewish state"?
Ironically, Serbia, under Milosevic's leadership in 1999, used a similar argument to cleanse itself from its "unwanted Albanian minority", (of course under the pretext that Kosovo was central to Serbia's ancient heritage and religious past).
Consequently, the act of compulsory population transfer (Ethnic Cleansing) has been accepted internationally as a war crime, and on that basis both Serbia and Iraq were subjected to international condemnations, and U.N. resolutions were enforced by military action to stop and reverse these war crimes.
For the moment, let's assume that the above argument are nonsense to the average Israeli or Zionist. Let us analyze why the integration of Palestinian refugees into neighboring host countries is not viable for the following economic and political reasons:
Economic reasons
It should be emphasized that 75% of the new Jewish immigrants to Israel, after the 1948 war, operated looted Palestinians houses, farms, cars, truck, banks, and the infrastructure resource such as water networks, the power grids, railroads, airports, wells, the telegraph network, and the schools, roads, and ports.
In other words, Israel has had the looted Palestinian capital as collateral, German compensation money for war crimes committed during WW II, and over 120 billion dollars in American taxpayers' money to help settle the new Jewish immigrants. On the other hand, Palestinian refugees and their corresponding host countries had no such good fortune. If Palestinians are to be helped to settle someone else's country, they have to take somebody else's property, which is unfair and unjust to others. From an economical standpoint, the biggest economic boost the "Jewish State" had was the looted and stolen Palestinian properties.
For a second, let's assume that such repatriation is possible in the host countries, and calculate the cost of such repatriation. For example, let's assume that we need to provide a reasonable health care insurance (not government subsidized) for each Palestinian refugee in Jordan (which hosts close to 3 million Palestinian refugees), and let us also assume that such insurance costs a $100/month per refugee. So the total yearly cost of providing health care insurance to all refugees in Jordan is at least 3.6 billion dollars = $100 * 12 months * 3 million refugees. Note that we have not yet analyzed the costs of providing infrastructure services, i.e. roads, water networks, power grids, education, transportations, ports, airports, ...etc. While contemplating these staggering numbers, keep in mind that the annual budget for the Jordanian government is little over 6 billion dollars, compared to 53 billion dollar for Israel.
While the average Jordanian citizen has some kind of collateral (such as land, real state, ... etc. ) to support his or her future well being, the average Palestinian refugee has nothing but his or her tent as collateral, and even the tent belongs to the United Nations. Consequently, the net worth (in economic terms) of the average Palestinian is almost nil, which negatively impacts tax revenues in the host countries. In fact, the huge number of refugees stifled economic growth in these host countries for several decades-since many essential services had to be diverted to help the refugees.
Ironically, the absence of the Palestinian economic base has motivated the average Palestinian to invest in his or her intellectual capital. It's really amazing how many Palestinians live the lives of many Jews in the past. In general, Europeans used to restrict land purchases by their Jewish citizens, which in return motivated many Jews to invest in their intellectual capital.
For the moment assume that the above economic formula is nonsense to the average Israeli or Zionist, then let's ask the following questions:
If it's easy for the host Arab countries to integrate Palestinian refugees into their economic and social structure, then why after three decades of Israeli military occupation of the West Bank and Gaza Strip, has Israel been unable to improve the lives of the Palestinian refugees under its direct control?
If it's easy for the host countries to integrate the refugees (despite their limited resources), then surely it should be much easier for Israel to do so?
Paradoxically, many Palestinian refugees' economic situation has actually worsened under Israeli occupation, and if it were not for United Nations' food rations, many refugees would have starved by now! In fact, malnutrition among Palestinian Children in the occupied West Bank and the occupied Gaza Strip has increased by 1600% since September of 2000.
It's unfair to claim that many Arab countries did not integrate Palestinian refugees into their economic, social, and even political structures. Out of the 5.9 million Palestinian refugees, there are 3.5 million refugees who still live in refugee camps (usually known as "registered refugees"). So despite all of the above obstacles, some 2 million Palestinian refugees (almost half the number of the Israeli Jews) are already integrated into the host countries' economic, political, and social structures