There are different ideologies that fall within the broad spectrum of "Libertarianism" as it is used in America. They are all bad, but some are "misguided but good at heart" (and better than, say, a Democratic-establishment Liberal) while others are "you have to be a literal sociopath to believe this". The latter tend to get signal-boosted more because they get funding from right-wing foundations and think-tanks.

Most ordinary people who identify as "Libertarians" would be Socialists of some sort but have been brainwashed by Capitalist propaganda that Socialism is bad and evil and is also when the government does stuff, and the government is bad, so Socialism is bad.

The logical extreme of Libertarian thought is Anarcho-Capitalism: the belief in the Non-Aggression Principle (that no-one should ever restrict another's freedoms, including their freedom to use their private property as they see fit), that coercion does not exist, contracts are sacrosanct, and that people have an absolute right to control what happens with the things that they own. This of course runs contrary to things like "Worker's Rights" or "Anti-Discrimination Laws"; and is also where a lot of the Pedophilia stuff comes from, since children are either (1). property of their parents (in which case the parents, as their owners, should be allowed to abuse or prostitute them) or (2). free actors in society (in which case they should be allowed to give consent or prostitute themselves). The ultimate issue with Anarcho-Capitalism is that its logical endpoint is Neo-Feudalism: if you own land, you have the right to dictate what the people living on that land are allowed to do while living there; there are no Tenant's Rights (in fact, like I said before, the only right you have under Anarcho-Capitalism is your freedom to act as you please on your own property, with your own property, without interference from others). Thus, Landlords become a new sort of feudal government, with complete power over their fiefdoms.

There's also Randian Objectivism, which is a rationalist philosophy whose main influence on modern Libertarianism is the Randian Ubermensch: living your life independently, to the pursuit of your own happiness (and only your own happiness), without care for the social rules of society at large. Batman's creators have cited Randian Objectivism as a major influence; Batman is the archetypical Randian Ubermensch: wealthy, white, egotistical, and living outside of society and its rules and laws (while benefiting from them).

There are more moderate forms of Libertarianism that believe in things like Net Neutrality (that the internet, like a public service, should treat all traffic through it equally, not giving preference to certain sites or companies) or the Right to Repair (the right to repair something you own personally, rather than having to take it to a licensed repairman). It's important to note that both of these run contrary to Anarcho-Capitalism: under Anarcho-Capitalism, an ISP has a right to treat traffic through its tubes however it sees fit; and a company can lease its products with whatever anti-repair clauses it wishes. There's also Right to Roam, which is very popular in Europe (but less so in the states), the idea that you should be allowed to travel through private land, as long as you do not mistreat it.