https://www.hrw.org/news/2007/11/19/gaza-israel-blocks-670-s...
https://www.independent.co.uk/news/world/middle-east/palesti...
From a cursory reading[1], it seems Israel had for a long time the ability to veto any human's exit from Gaza through the Rafah crossing in Egypt. Seems to only be the last 5 years where they were not able to do this and that border crossing was open. I graduated from University in 2017.