Why is the lscache directory excluded from a user's disk-usage calculations?

Question

Why is the lscache directory excluded from a user's disk-usage calculations?

Answer

The /home/$user/lscache directory is owned by the nobody user. Directories and files owned by the nobody user do not count toward a user's disk-usage calculations.

You can read about how LiteSpeed sets the permissions on the lscache directory in their documentation here: Example: Cache Directory and File Permissions.