It's a layman's take. That part where he says "guns are useless" is kind of telling; the only weapons employed in space so far have been 23mm cannon.
I did the math once, either here or on Reddit, to demonstrate that hitting an object from one orbit to another with a kinetic energy weapon of any kind is really really tricky. Thing of it is, though, once you've expelled that little nugget'o'death out there into orbit, they never go away. So yeah - you're 20,000km away and I fire a shotgun at you. You've got time to move. But those shotgun pellets are now an intimate part of the solar system, and they're going to whizz about until they hit something. Any sort of orbital combat is rapidly going to become an exercise in area denial: one busted-ass Chinese satellite and you've got a perpetual cloud of kinetic death consisting of more than 2300 objects bigger than golf balls. Missile? Shit, son, I don't even have to get close. I just need to put up a cloud of shit between you and me and your freedom of movement becomes distinctly curtailed. "Fighting" becomes a near impossibility; "fucking shit up to the point where nobody can fight" is the easiest thing in the world.
Harry Harrison argued in the Stainless Steel Rat series that interstellar warfare was simply impossible because of the logistics. "Realistic space combat" probably happens at the UN because it's not " fought between sports cars painted with phosphorescent paint, with machine guns mounted on their hoods" it's Asteroids where the bullets never go away and the rocks never get small enough to ignore.