They CAN;
Just because my friend drops his Thompson off a cliff and it doesn't break, doesn't mean I can do the same!!
I have seen that video as well, and that was a pretty cool test with promising results. But that doesn't mean it neccesarily "Applies" to your gun, whether it gets damaged or not depends on Surface, GB position, Height, Speed, all kinds of FActors.
That video is just to show you how strong the Replica CAN be, Your gun really should never need to deal with punishment like that.