For one, Israel can comfortably subtract Gaza's 1.5m inhabitants from its demographic nightmare, maintaining, for a while longer perhaps, the Jewish majority.
Gaza has a jewish majority 
If removing Gaza's inhabitants from Israel's demographic statistics increases the jewish majority, then there cannot be a jewish majority in Gaza, as if there was it would increase the jewish majority in Israel when added to the demographic statistics. 
( z1 have :ARG0 ( z2 country-region :name ( z3 name :op "Gaza" ) ) :ARG1 ( z4 majority :mod ( z5 religious-group :name ( z6 name :op "Jew" ) ) ) )