I would generally agree with this... even though I have done only a little mountain biking. But some of the last section, with the steps and drops and rocks, I don't think I could have done regardless of the speed. For example, from 24:04 to 24:12. That little section would probably have me walking the bike. Several others like that too.
Its a good point. I just watched that specific section. The rider actually went around several of them, which I totally would have done too. But the last two--a drop where he skipped a switchback, and then a step on what is clearly a hiking trail ordinarily, yeah, I'll admit, I'd want a closer look before deciding. Which in reality would just mean, if it was my first time down, I'd walk the bike around it.
However, if you haven't been on a modern FS MTB, you would be shocked at how irrelevant some of those rocks and even the steps from the earlier part of that sequence are. The biggest danger with those rocks is not the rocks themselves but the possibility of wedging a tire between two of them and going endo. That's the novice mistake, because it seems easier to go between than over. But over (or better yet, around altogether) is the safer way.