Best Answer: Because the democrats don't understand what Socialism is. They think that all socialism is is the use of taxes for government services. The democrats don't realize that socialism is the take over of production from what would have been provided by private organizations, often said take over are done violently. They think public schools is socialism when it would only be socialism if it was illegal to have public schools or home schooling. The presence of competition is one of the factors that make it not socialism.
Social Security, Medicare, Medicaid, Free Public school education are all examples of socialism.
The Democratic Socialists want to broaden these benefits for everyone- so the working class and the poor don't pay king's ransom just to get health care, etc. Scaring people with 1940s socialism is a tactic Trump and his followers are trying to do with the American public. Wait and see what they offer. You may find it worthwhile.