This way paparazzi can take pictures but it's hard to distinguish the shapes.
But now probably pretty much anyone in their bedroom could do it in a few hours. Literally next post after this one is for https://vgg-t.github.io/
The surveillance state is here
Meanwhile, positive facial identification attaches to all kinds of legal and intelligence infrastructure. Now, you can be charged with crimes, have a warrant executed against you, can be accused of supporting terrorists if you show up to a protest, etc.
I suppose I don't think the criticism is wrong, but it seems to presume that this is new information not previously understood rather than an intentional calculated risk.
If you don't think there is a disadvantage to looking different in a protest, think about the "qanon shaman" from 1/6 him looking different totally made him more of a target to being identified.
I don't think "camouflage" fits any definition of what Qanon Shaman was wearing, either in a general sense or in the tactical sense we're talking about here.
Also if you have a distinctive face paint then your image might be shared more, or just noticed more in the images that are shared to give more opportunities for people to recognize you or to remember your face to be recognized latter.
Also having a distinctive face would make it easier to track in different sets of footage especially when the technique was originally demoed in 2011.
It's not to say it wouldn't ever happen, but there's an order of magnitude difference between that and guaranteed positive identification which is what informs the calculated risk.
It won't "work right" on cameras that have permanent IR filters. Maybe. I haven't tested this in years.
I have a feeling that IR of the correct strength and frequency would be dimly visible to humans, though. Similar to cameras with monochrome night vision via IR LED.
I worked in enterprise FR, on one of the globally leading systems, as the lead developer. That scenario defeats pretty much all FR when from a single camera. It can be mitigated with multiple camera views, which few FR systems are setup for multiple quality views at every key location.
(Now I wonder, how narrow-band such IR LED is, and if it could be made to emit a single frequency so sharp, it would create funny diffraction patterns off cameras' surfaces and lens imperfections, clobbering the high-frequency components of the image...)