You cannot reason someone out of a position they did not reason themselves into.
People here have seen the names "Musk" and "Branson" and decided the technology much be a fraud and subsequently sought a rationalisation to validate their emotions.
I watched 20 minutes of the first Thunderf00t video. It is a classic example of a "gish gallop",
en.wikipedia.org
Very reminiscent of the arguments we used to get against renewable energy. It assumes that any problem they can think of is insurmountable and evidence of their staggering genius. Its starts with the usual childish nonsense of "its never been done before therefore it cannot be done" in terms of the size of the vacuum tube. Its makes a farcical comparison with the Glenn Research Center's Plum Brook Station as "proof" you cannot enclose a vacuum of the hypothesised volume. That structure is a open area dome where the loading has to be taken by the dome and spread to the side walls. Where as the hyperloop would be a tube. This will have a fraction of the mass in terms of the structural loading it has to bear. Submarine pipes and submarines the vehicles carry vastly greater pressure loads. This is pure bad faith argumentation.
They go on a bit about expansion. A legitimate engineering problem but one found in surface gas pipes around the world. We have airtight pipes in the deserts of Arabia and the wastes of Siberia. How this is supposed to be a gotcha is beyond me. Its more like the video creator thought of a problem and did zero research to see if others had come across the problem and had existing solutions.
They then go on in lurid details about the problems of a failure. It is not a balanced look at what could break a tube strong enough to hold a vacuum. Not a look at similar existing structures and how often they fail, just making the trite point that a failure would be catastrophic over and over again. They seem to have made zero effort to ask people who have knowledge of the project what their response to these issues would be.
I see nothing constructive or of value being offered as a critique.
I do see emotive people seeking validation.
The validity of the technology will depend on the costs and scalability. Like every other technology. The prototypes will work badly, fail, be very costly and easy to mock. Like every other new technology. Criticism is easy. Engineering is hard.