To me, if he is presenting math as magic at all, he's more like Penn & Teller than David Copperfield. He uses a hook to gain your attention, then explains the trick clearly to show that there are no devils, there are no demons, it's all just science.
I mean, really, what more do you want out of the guy? He's getting people interested in math. Let's try to at least be a little more constructive in our criticisms towards him.
That project helped them reason about higher-level math in a way they never thought themselves capable. The idea of "magic" never came up, but they certainly spoke about their sense of wonder at higher-level math. I really appreciate the way he presents mathematical concepts.
The one linked in the submission is more of an obvious statement hidden by obscure use of language. Slightly silly, but not very bad.
The worst offender with "magic" is the one with the Riemann zeta function [1], which went viral a while ago. The problem here is that they get people started off on the wrong foot, confusing them with wrong arguments and hidden definitions. Now, if people really want to understand why this can be made meaningful, you first have to explain that the better portion of the video is absolutely wrong, and only then can you explain what is actually going on.
I remember my professor writing an equation, doing the proof, then exclaiming "This obviously reduces to this, QED!" and the entire class staring in disbelievement. It really did seem like she was inventing math as she went, and took a long while to really get a grasp of how to think about a proof when doing one.
In my personal opinion they always explain quite carefully, using neat and concise diagrams. My old maths tutor used to have a similar teaching style, which worked very well.
The post editing even adds further explanation when the editor believes certain things haven't been explained clearly.
The trick here is that they start with the intuition of counting, in which each number is itself a single thing, but are actually doing a calculation based on each number being a string of single digits.
It's much less shocking if you say: Picking a random 10 digit number is the same as randomly picking 10 single digits. The more digits you pick the more likely it is that you'll get a '3' somewhere in there. So as your string of numbers increases in length the less likely it is that you're string won't contain any given number. If I said to someone "The more dice you throw the more likely it is you'll get at least one 3", I don't think I would get anyone who was surprised by that.
The unfortunate thing is that math and number theory in particular are full of genuinely fascinating observations that don't rely at all on a tricks of phrasing to be revealed, and rather than making less math literate people feel 'dumb' (as these videos tend to do), spark in interest in exploring math further.