Without being too reductive, Stallman and others apply extreme cynicism (assume the worst case scenario will happen), and they are "always right" because the naysayers seem to apply undeserved optimism. Companies like Slack initially try to appeal to the freedom crowd (IRC gateway), until they decide it impedes their business model. Stallman can see it coming from a mile away because he correctly views people and entities from a cynical perspective that many others aren't used to doing.