Neck beards aren't a libertarian thing but libertarianism is a neckbearch thing. From reading your comments, it seems you have have trouble understanding causation/correlation and cause/effect in general.
Fedoras and trilbies are just hats. There is nothing inherently wrong with those types of hats but the way neckbeards wear them is inappropriate. Those types of hats are almost formal and should be worn with a matching suit or vest. Neckbeards wear those hats with silly t-shirts and shorts.
Libertarianism is just a political ideology like conservatism or liberalism. What makes it different is that neither of the two main parties in the US identify as libertarian (for the most part). Lots of different types of people are libertarians. For example, many CEOs and business people lean libertarian and love Ayn Rand. None of those people are Cheetos eating neckbeards who spend too much time on Reddit.
Speaking of Cheetos, those are just an unhealthy snack food. Key word in that last sentence was "snack". Neckbeards turn that type of snack into a meal regularly.
Cryptography and Computer Science are great fields to know about and be involved in. Without Computer Science, we wouldn't be browsing Reddit right now. Without good cryptography, things like online banking wouldn't be possible. Most Neckbeards are fans of Computer Science but don't really know anything about it. I've been taking Comp Sci classes for a few semesters and there are a lot of Neckbeards in the classes. The only correlation I've noticed between having a Neckbeard and being in the class is that Neckbeards tend to be worse at Comp Sci than normal people. They'll talk game, drop buzzwords, drop names, etc. but when it comes to actually making anything work, they fail hard. Even the simplest concepts are beyond their understanding. They don't understand pointers, objects, abstract data structures, or sometimes even simple keywords. For real, I've heard people say they don't understand what the "this" keyword does in java.
I could go on an on, but I think I made my point.
The real question you should be asking, why is Bitcoin a Neckbeard thing? Hint: It is related to why Neckbeards like Fedoras, Libertarianism, Atheism, and Comp Sci.