Did you read it?
Let's cut out some parts of it to make it easily understandable:
You hereby grant Blizzard a - right to - enter into computer memory, and use and practice such User Content as well as all modified and derivative works thereof.
That means that Blizzard has a right to put your work into their computer memory.
Let's cut out some parts of it to make it easily understandable:
You hereby grant Blizzard a - right to - enter into computer memory, and use and practice such User Content as well as all modified and derivative works thereof.
That means that Blizzard has a right to put your work into their computer memory.