Firstly, the article in question is about the technical feasibility of hyperloop, which is in question because it's not something that's ever been done before and it's a non-trivial application of aerodynamics et al. Secondly, if you insist on changing the subject from one of technical feasibility to one of economic feasibility you can't just spew a bunch of opinions without backing any of them up. This article isn't meant to address the economics of hyperloop and implying that it should is unfair.
The entire point of the comment you're talking about was to point out that the nature of the most substantial critiques of the Hyperloop were economic and not (to use your term) "technical". It's your comments that are unfair.
Also, none of these are my opinions; they're opinions distilled from published critiques of Musk's plans. I didn't simply make them up.
It's easy to write off what I've said as overly critical, especially since the underlying sentiment has some valid points. But here being right for the wrong reasons or being close enough is just not acceptable. Precision isn't just important, it's everything. Whether HSR or hyperloop we're talking about a cutting edge multi-billion dollar infrastructure project. Californian highspeed rail is expected to cost more than the Manhattan project (adjusted for inflation). This is not a topic that allows for sloppiness in its discussion.
If a technical article about how facebook is able to scale was posted to HN and then someone made the comment: "Everyone knows that scaling java services is easy, the real problem is that facebook doesn't have a clue how to monetize effectively." people would jump all over them. Regardless of whether or not the criticism of facebook's monetization strategies was accurate. When you make a fundamental technical error on that scale it immediately red flags whatever point you are trying to make, and if the rest of your post is just assertions and opinions with no backup then your post should be ignored, and rightly so.
If you want to talk about multi-billion dollar high technology projects and you don't care about getting the details right then I suggest you go to the bar and discuss things with the other patrons there. If you want to have a serious discussion though then you better come to the table with the correct facts.
Firstly, the article in question is about the technical feasibility of hyperloop, which is in question because it's not something that's ever been done before and it's a non-trivial application of aerodynamics et al. Secondly, if you insist on changing the subject from one of technical feasibility to one of economic feasibility you can't just spew a bunch of opinions without backing any of them up. This article isn't meant to address the economics of hyperloop and implying that it should is unfair.