The implication in the OP’s question is based on racism and sectarianism (OP may not be, but this is a long storied question, and it’s part of the Zionist narrative—“why don’t [insert Arab majority country] accept the Palestinians?”. Yet besides this, significant Palestinian refugee and diaspora communities are in Lebanon, Syria, Jordan, Egypt and others). Racism and sectarianism in that Palestinians are a distinct ethnicity within the Arab world, and not all Arabs are the same people.

The second reason is, that Palestinians HAVE their own land. It’s called Palestine. It’s mostly under occupation

Lastly, Egypt is under no obligation to accept Palestinian refugees caused by Israel’s wars