If you ever indulged in the wonderful way to irreversibly waste time and lose faith in humanity in the process that is political discussion, especially on the Internet, you have probably noticed that from some degree of extremism onwards, its different kinds appear to stop ideologically diverging from each other and instead curve around and grow more similar, coming astonishingly close at the very extremes to the point of resembling something akin to a horseshoe shape; with some "wonderful" stances such as national socialism seeming to bridge the gap between two opposite ends of extremism and creating a whole new level of awful that takes the worst parts from both.
Using the popular political compass model which presents the political spectrum as a 2-dimensional Cartesian space described by two axis, economic left-right and lib-auth, and political beliefs of an actor as a vector pointing outwards from the 0 point which represents either some status quo or an arbitrary point considered the ultimate neutral center, we can start to see hints why. As political position presented in this way is essentially a divergence from the beliefs considered neutral, at some point the variety of ways to diverge simply starts to run out, leaving more and more limited options to go further, and forcing people of wildly different approaches to take increasingly similar paths.
Afterthought: if I understand the involved geometry correctly, this should work with all n-dimensional "compasses", such as the 4D "8values", creating n+1-spheres. This then poses the question if the additional axis (let's call it aa) will retain its characteristics in those cases or will possibly differing ways the different scalars influence the final retardation of the resulting political stance vector simply increase the noise and strip aa of any meaning other than "distance from neutral".