DemSoc itself is a bad term. It either is used to refer to Reformist Socialism (which is an impossibility and thus akin to astrology) or to pretend Marxist Socialism isn’t democratic, advocating for factionalism and other possibilities of Socialism itself being destroyed by international moneyed interests and domestic wreckers.
There are numerous reasons for this. Stability in protecting revolution and genuine popular support are among the larger and more important reasons.
Neither are Capitalist states, and neither was Marx. Combatting international Capitalist influence was and is key for retaining Socialism.
Not true at all, actually. Those controlling the media want you to think it though.