Like, really? What could a beta who snapped do that's the slightest bit worse than a CN protagonist? CN Protagonists cripple you, kill you, cut you into pieces alive, some eat you alive, some kill your family/clan while snacking on your girlfriend before crippling you and sending you into an endless void with forced immortality and artificially help you get OP there from an insane desire for revenge... and just when he gets out of that space he gets crippled again and laughed at... then... maybe... maybe... killed.
I know that it's a meme by now that a "good guy that snaps is scary", but the worst the JAP MC could do to a CN MC is doing the same to him (CN MC) as was done to him (JP MC).
Yup, beta MC is synonyme for JP MC for me.