Just because someone is proposing something for a small slice of society, doesn’t mean they intend to propose something similar for all of society. For instance, insisting on free schools, free (rail) roads, free health care, free water, and nationalised energy plants doesn’t mean they want to make everything free, or that they want to nationalise everything, or that they are nostalgic for communist Russia or whatever. That’s just the Red Scare talking. The fact is, different systems for different slices of society can and do coexist.
Human nature is not limited to the environment we’re currently living in. Genetically we’re barely different from the people of a couple hundred years ago. And yet our ancestors lived under many kinds of societies. It would be a little presumptuous to assume the one we’re currently living in is the best. Especially considering how it came to be: remember that as Thatcher was saying capitalism/neoliberalism was natural, she did "nudge" things along by having the army pay a visit to workers on strike.
Even communism isn’t a monolith. It took various forms, which failed for various reasons. Sometimes it was direct outside interference, like how the Paris Commune was basically crushed by the national army.