What it looked like (to me - a young, uneducated dummy) is that the drain bolt was the first thing to contact the ground and subsequently was torqued back and up into the case, shattering the part of it immediately to the rear of the bolt. If there was a low-profile bolt and/or a sufficiently thick skidplate then the bike may have been just fine. Well, or the frame could've been completely boogered - it's all speculation in the end.
What ISN'T speculation on my part is that it's just... dumb to do this to a 31-year old bike (an antique!). Especially when there's a great many other KLRs that have been abused to the point of almost not running which would all be perfectly suitable for this kind of destruction. (and, in my opinion, may even be a better candidate for such tests if you take that prior abuse into consideration in the final cut of the video)