why doesn't Elie celebrate with them Rosh Hashanah and Yom Kipper?

Eliezer refuses to celebrate Rosh Hashanah and Yom Kippur. Though he does not doubt God's existence, he does question his justice, and he accuses him for the existence of concentration camps. Eliezer's father does not want to observe the religious holidays either, although most of the other prisoners do.

why doesn't elie celebrate yom kippur and rosh hashanah