> Blizzard actually provided significant help in creating “Make Love, Not Warcraft” which shows just what transformative reuse can look like.

Actually, it shows how copyright owners can cooperate when a third party's use comports with their interests. If, however, South Park had appropriated imagery, music, etc., from Blizzard without permission, then that may have been copyright infringement outside the realm of fair use. (Note: South Park probably still could have parodied World of Warcraft, albeit without using any of Blizzard's materials.)