Speaking purely personally, "the most advanced form of scientific socialism" is because this is the main tendency attempting to grapple with failures of past and present communist movements (including it's own). Most of the time I get in conversations with MLs about these MLM parties, especially the ones involved in armed struggles, there's often heavy resistance to paying them any sort of mind or any because the PCP lost or the CPP haven't won yet or the CPI(m) call China imperialist. I just want some comradely critical analysis instead of "Gonzalo personally ate one million babies, checkmate ultra" 😔