He...encourages caution. It's one thing to call a technology "debunked", another to say it's very difficult or that it has a low probability of success.
Thunderf00t is not a credible source, even if he's right sometimes, it's in the "a broken clock is right twice a day" sense. So these aren't good videos.
He is a scientist with published papers, and he seems to have a decent understanding of physics.
Obviously scientists are not perfect, but you seem to imply that most of his videos are incorrect. I can't see any evidence to support that, but I'm happy to be contradicted.
https://www.youtube.com/watch?v=JAczd3mt3X0
He...encourages caution. It's one thing to call a technology "debunked", another to say it's very difficult or that it has a low probability of success.