You can’t say the entire system is corrupt because of Capitalism and then also put faith in the system to deliver an outcome that isn’t just more Capitalism.

Isn't that exactly what your original post just suggested? That some how strengthening capital, peeling off anger and activism toward a rightward political shift, and defending the corrupt institutions of the status quo in order to get elected will somehow then allow a right wing Labour Party to go against it's own interests to somehow enable the left.

Maybe I'm missing something in your arguement.