***** A NON-TEACHER's COMMENT *****
(1) I believe that the "humor" of the comic strip lies in the fact that
the children are using "closure" incorrectly.
(2) When someone wants closure, that usually means that s/he
wants to put an end to a painful experience.
(a) I shall give an example -- carefully. As you know, on September
11 ten years ago, something horrible happened in New York City.
Since that day, many people have been very sad and cannot forget
about that day. As you also know, a few days ago, a certain person
was killed in a certain country by United States armed forces. For some
people, that has helped bring about closure to a very painful experience.
(3) In the cartoon, the children use the word incorrectly. They are
not thinking of mental pain. They are referring to the fact that their
mother wants them to keep the fridge door closed!!!