When  it comes to vilifying Israel, hyperbole and total fraud are the rule. This is true of one the main things said about the Gaza Strip in order to cast Israel in a bad light. But Gaza’s population density is not Israel’s fault. And anyway, Gaza is far from the most densely populated place on earth. But if there are those who truly believe, or really, really need psychologically to believe that that claim is true, then there is  a solution. Allow Gazans to emigrate from Gaza. There are several Arab countries with much available undeveloped land. There are also quite a few non-Arab lands that could absorb Gaza Arab immigration.

Here are population and area stats comparing the Gaza Strip with Manhattan Island. You can calculate the density by dividing total population by area (in square miles or square kilometers).
Manhattan  Island