Hydrogen electrocatalysis (HER/HOR) exhibits an anomalous, non-Nernstian pH dependence that has motivated competing mechanistic narratives yet still lacks a unified, transferable, and quantitatively predictive description across conditions. Here, we introduce a theory-neutral waveguide kinetics framework that reinterprets the polarization curve as a power-flow-like response, enabling a compact modal representation of interfacial kinetics. Without presuming any specific mechanism, the model quantitatively fits four representative polarization datasets historically explained by divergent theories. From each fit, we extract interpretable diagnostics, including a reflection amplitude and a useful-output density, that provide transferable metrics for interfacial efficiency. The framework thus establishes a computational experiment platform for mechanistic triangulation, operating-regime diagnosis, and the rational design of hydrogen electrocatalysts across the pH spectrum.