In my opinion, that definition is ass backwards as it applies to America. Unlike other countries -America is quite different. In America the government IS comprised of the citizens; society -government does not rule society; society rules government. Minimal state intervention is achieved through limiting government.
In America, Libertarians have a problem with society -specifically with social order. As such, it is easy to see WHY libertarians are actually leftists BECAUSE they support efforts to impose via government tyranny minimal societal intervention in the role of governance.
Neither extreme of libertarianism nor statism is tolerable, but a healthy societal balance can be found somewhere between the two. The Country was founded on principles that shunned the constraints of statism.
I’m not in disagreement with the argument that the Libertarian Party is a breeding ground for Leftism.