When these aliases were made:
The contents of the wikis were copied over instead of being renamed. They have identical content, but the older wiki pages (on the left) have more history. Therefore, the newer ones (on the right) should be deleted. Then the old ones should be renamed to take their place, since the newer ones are the tags in use.
Note: Be careful not to delete the good wiki after someone else renames it.
Related: topic 7690/p43