Can you unencrypt / remove encryption from a user home folder? [duplicate]

Yes, you can. The short and dirty description of how to do it is this:

1. Copy your files out of your home directory to another (unencrypted) location.
2. Move or remove the encrypted home directory out of the way.
3. Restore your files.

The actual process is more complicated than this. The Ubuntu Documentation assumes you've already moved your data without telling you how; this description from Virtually Machine shows you how.

In short:

1. Log in as root.
2. Move the encrypted home directory so it mounts not on the home directory, but on a directory called Private in your home directory.
3. Move everything out of the ~/Private directory into ~.
4. Remove ecryptfs if desired.

See Virtually Machine for more specifics.

I would recommend logging out and back in just after the move: this makes sure everything is updated in your environment and so on.