"Democratic socialists" are basically just people who believe all the liberal propaganda that the liberal democratic political system is the only "true" form of democracy, but they're also a socialist, and so they try to reconcile these two contradictory positions by imagining that a socialist system will maintain a bourgeois political system with bourgeois parties running on a platform of abolishing the socialist state in opposition to the socialist party that wants to build one. They're convinced anything less than this is "authoritarianism" and bad because they genuinely cannot imagine anything outside of liberal democracy.