Time for a little 'nit-picking.'
As we all knoe, there is no AFCI involved. Nor, matter of fact, is a GFI built into the hair dryer plug. I believe the correct name is "immersion curent limiting device" or some such. While, by every description I have read, this thing is supposed to operate like a GFI, it seems that the testing protocols are different somehow.
For the thing to work, water has to get into it. I notice that this did not happen in the first video until the switch was submerged. Even in the second video, water may not have actually reached any live parts.
OR - and this is certainly possible - the product had a sham device, and a counterfeit UL lable. When a foreign country supports the counterfeiting of such things, nothing short of a naval blocade will have much chance of making any difference.
Just, for the sake of argument, assume the device is legit. Having the element in the water is no sure path to current leakage; it wasn't so long ago that every coffee pot and deep fryer had immersed elements. Many still do.
Likewise, a bathroom tends to be a humid, corrosive place. I would not be surprised to find that the manufacturer had coated everything inside with a clear laquer. This would also serve as an insulator.
As I see it, things like GFI's ought to be treated like parachutes ... you do everything you can to make sure they're never needed!
(Then again, I'm old enought to remember when skydiving was dangerous .... and sex was safe!