Why can't I just move the entire iTunes folder?

You can do that. You can copy the entire Music folder and create an alias for where it normally belongs. However, OS X will not allow you to delete the entire Music folder without a little extra work:

Copy the /Home/Music/ folder to the desired new location. Create an alias to the new location and put the alias in the /Home/ folder. You will now have a "Music" and a "Music alias" in your /Home/ folder. Open the Terminal in the Utilities folder. At the prompt enter:

sudo rm -rf ~/Music

Press RETURN. Enter your admin password when prompted (it will not be echoed) then press RETURN again. The old Music folder should disappear. Now rename the "Music alias" folder to "Music".

See other posts about this topic. iTunes is pretty good at not being fooled by aliases and symbolic links.

Since iTunes is pretty much all that's in the Music folder, then why not move the entire folder? Aliasing it will work for everything in the folder.

Nevertheless, you can do the same thing for just the iTunes folder if you wish. Same procedure.