The 8 Bit Guy does address that in his video, by pointing out that the car was on Autopilot, not Full Self Driving, in that test. A subtle distinction perhaps, and questionable how much difference it should make to forward collision detection.
Someone else repeated the test with FSD and it seems to depend on the version you have. Older cars with V3 hardware will crash into it, newer ones with V4 will stop.
It's a well known issue with Tesla systems. Certain things confuse the vision system, and they have tried to mitigate it with new hardware, but it's still not perfect. It's also rather unfortunate for people with older cars, who get a flawed and dangerous product. Musk promised free upgrades, but is now not offering them on the basis that they are only needed to keep you from dying and otherwise the system "works".