The way this mount is being marketed has a lot of players thinking the ONLY way to get it is with a 6-month sub. Even when you go to the shop for the mount itself it says to get it with a 6-month sub but you can just buy it for $25.
Based on the some of strategies used by Blizzard in the past, this comes off a bit manipulative. Some people are getting the 6-month sub just because they want the mount.