Prior to getting into libertarianism, I never much thought about the existence of an objective reality. I always took it for granted that, the universe exists regardless of our perceptions, and our perceptions of it were just the means by which to interact with it. When I first began reading Murray Rothbard, Ayn Rand, and Ludwig von Mises, I was thus utterly confused at how much time they spent explaining that reality existed.
As I got more involved in libertarian circles, as various terminology came about to describe factions within them, and as I more and more frequently found myself arguing with non-libertarians, this requirement became more evident. There are no shortage of people who make willful choices to ignore reality, and others who outright reject its existence. This shocked me when I first became fully aware of it, as I had always been under the impression that people who had bad interpretations of reality were simply misled. Be they religious fanatics who were certain God were guiding the actions of man, or be they leftists who disregarded well documented lessons of history, I always thought they just needed to be better informed. I came to realize this was not the case, and that it was a threat to my liberty and safety.