I'm with FF that there's little appreciable difference between or sense in the modern parties. Both pay lip service to their extremes and then whip back to the middle for the election. This is largely due to the first-past-the-post voting system and the archaic electorate system that doesn't even relate to its actual use today. There's a reason the founding fathers wanted the original senators to be chosen by the state LEGISLATURES rather than the people. They were supposed to balance the chaotic sway of public opinion.
As for the topic title, pure socialists believe that people work the same no matter what stimulus you give them, or that they work better with negative stimulus rather than positive stimulus. There's a lot of jobs that just plain wouldn't get done if people weren't paid better to do them. The only people that want pure socialism are the ones that don't want to sacrifice for their own future.
Sorry I didn't watch the interview. I really don't care about the DNC or news anchor bobble heads. Those shows are an anachronism when much better info is on the web. Most mainstream news programs don't even bother fact-checking anymore, At least I can fact-check for myself on the web rather than listening to hot air or filler stories.
Socialism works in economic spaces when public resources are not taken into account or private ownership is not possible. Fishing is a prime example of an industry that requires government controls to keep companies from cheating humanity into culinary poverty because of their own self-interest. I hunt and happily abide by the laws and regulations for wildlife because it is a public resource that should be passed down and enjoyed for generations to come. Air pollution, water pollution, and transportation are all places where there just isn't enough stimulus (or too much risk) for private companies to function well.
Regulated capitalism works in those parts of the economy where most private decision-making is beneficial to both companies and society as a whole. Government offers some services that companies shouldn't themselves (like enforcing contracts or worker treatment) or provides the necessary motivation for companies to act in society's best interest.
Pure capitalism has never existed, except possibly in the drug trade or other black markets. Even those rely on government currency rather than barter, although those actors enforce their own contracts in their own special way. It's possible that North Korea is actually a capitalistic actor if you consider the entire country an independent company that disregards all international laws. I don't think anybody wants companies treating their workers like North Korea treats its citizens. And trust me, companies will do anything to make money if there's nothing that stops them. Never underestimate a the corporate citizen's disregard for common human decency. The Stanford Prison Experiment proved a long time ago that people will do immoral things for what they consider the group good, whether as prison guards or executives. Too many people forget that modern labor and safety laws were won by workers standing against Pinkerton guns hired by management. You would still have children losing arms in threshing machines today if it were not for those workers.
A class environment is necessary to motivate the clever to work themselves up and the rich to maintain their status. If someone doesn't value their status, that's a perfectly sane way to live, but they should recognize that society is better off if innovators have a reward for their work. I think Northern European countries do it best by allowing the status differences, but making things more a little more even once you get past the stupid money level or if you're in the dirt poor level.