Here is a bit more detail of the section in the center (click to enlarge):
While parts of the town are certainly crowded, it looks like plenty of people are living in houses where there are lots of trees. This looks just like any suburban US community. (This is not the "refugee camp" next door, which certainly is more crowded than this. But the school was apparently in Jabalya, not the camp.)
"One of the most densely populated places on Earth."
See also my recent video on the same theme.