This issue is almost entirely caused by the relationship that Jagex has with its player base. In 2012 Jagex released a rolled back version of the game to 2007 as many were unhappy with some of the updates that had been implemented over the past several years. One of the primary components of OSRS(the rolled back version of the game) was that every update put into the game had to pass a community poll with 75% approval or more, otherwise it would not be implemented in the main game. As the games age began to show, a series of third-party clients that could run the game began to emerge. Many of these clients provided funcitonality that the main game client could not support, but drastically improved the users game experience. WIth this Jagex was forced to begin co-operating with third party clients or risk their game dying completely.
In the last year the company has been running into issues where it is hard to distinguish between a third-party-client and a bot script. Leading the company to rethink their relationship with third party clients. To respond to this they have begun re-writing their entire game client in order to support the features the users want, so that they can eventually stop support of the clients. However, the game community has become used to being able to write their own plugins, and tools to make their game life easier,that the company has stated multiple times that they were NOT GOING TO IMPLEMENT. Now they have realized that they want to do these things, and are saying to hell with everyone who has devoted their own time and effort into improving the game that they love so much.
Yes, Runescape is owned by Jagex, and everything in the game is subject to their rules regarding their intellectual property. However, They have had every opportunity to shut this project down for the last few years, and said nothing until 48 hours before the release. By doing this they have shot themselves in the foot and have to decide which is more important. Their users, or what they would like to do to their game.