Project 5 why the big resitor?

this is a picture i took out of the user manual, i don’t get why it needs such a big resitor. a few projects before that the same led light will light with a 100 ohm resitor to protect it from overvoltage.

link to the user manual
https://www.vellemanprojects.eu/downloads/0/user/usermanual_edu02_uk.pdf