The mathematics indicates aspects of causal necessity, perhaps, in dynamical systems but we might turn to a complementary psychological ontology of polarisation, Othering and system differentiation.
A partisan point of view (or mind and associated political, ideological subjectivity) is always and already inversely anchored and dependent upon that which it is not. Any one partisan extremity, direction and asserted political identity is defined and refined as much (and inversely) by and of Other as it is of Self; this is what inflates the constructive dissonance of progressive, dissociative differentiation.
Here, two primary systems that both “contain” each other as a productive discontinuity and friction by and through which the gestalt self-propagates. The dissonance and inflammatory adversarialism is actually (an) optimal autonomous heuristic for political system self-propagation.
As for independent voices, here as elsewhere they are swept away in a tide of normative polarity and expectation that pendular oscillation between emergent poles is the nature of Democracy. Independent voices might indicate the communication medium and convergent mean of harmonic oscillation in unexpected ways, as saliences of information entropy.