How can people celebrate ethnic cleansing?

Whatever one thinks about the events of 1948 and 1949, the death and destruction are hardly things that should be celebrated.

"As a consequence of the fighting in Palestine/Israel between 1947 and 1949, over 700,000 Palestinian Arabs became refugees"

"One Israeli military intelligence document indicates that at least 75 percent of the refugees left due to Zionist or Israeli military actions, psychological campaigns aimed at frightening Arabs into leaving, and direct expulsions. Only about 5 percent left on orders from Arab authorities. There are several well-documented cases of mass expulsions during and after the military operations of 1948-49 and massacres and atrocities that led to large-scale Arab flight. The best-known instance of mass expulsion is that of the 50,000 Arabs of the towns of Lydda and Ramle. The most infamous atrocity occurred at Deir Yasin, a village near Jerusalem, where estimates of the number of Arab residents killed in cold blood by Israeli fighters range from about 125 to over 250.
"

from
http://merip.org/palestine-israel_primer/pal-refugee-citizen-pal-is.html

Here is a map of Palestinan refugees worldwide from :
http://mondediplo.com/maps/refugeesdiasporapaldpl2000

Here is a map of Palestinain refugees in the Middle East:
http://mondediplo.com/maps/refugeespalestiniandpl2000