You make it sound like they're making their own game and ripping off the Blizzard characters/mythos/etc, rather than using Blizzard's own content creation tools

You make it sound like they're making their own game and ripping off the Blizzard characters/mythos/etc, rather than using Blizzard's own content creation tools which they release in order to promote modding... What are they going to do, give you modding tools and then tell you you're only allowed to use them completely out of context of the game they came with?