Stan:
As usual, you seem to be in denial of facts, the laws of physics, and the history behind the rules. We argued before about the dangerousness of tubular structures on the front of cars when arguing over the mandatory crush structure rules for the front of the cars. Thankfully, you lost that arguement ( mandatory vs non-mandatory) and with the exception of the still-allowed tube nose frame on the FMs, the Directors saw fit to force the CRB to reinstate the rule last spring. The accident outlined here with a rear tube structure is a perfect example of why I argued for a ban on tubular structures on the front of cars, and the fact that you don't seem to recognize that example for what it is, is downright scary.
As an FYI, the reason originally for the rear frames on FVs was to keep guys from being able to purposely bump you out of gear - a pretty common practice for a while!

A side effect was that cars were then able to safely bump-draft, and as a result, most of the protective cages were made with a tall vertical tube that extended almost as high as any frames out there. The manufacturers all pretty much agreed for many years - outside of what was said in the rule book - to use that vertical tube for exactly those same safety reasons I've agued about. The result was that in contacts like this one,(and we've seen many over the years) the vertical tube always positively contacted multiple rails in the sides of the car being hit, spreading the load over a larger area and pretty much preventing any meaningful penetration past the rails. Protective cages with reletively small area ends like the one here can and will punch through cockpit side panels, kevlar being present or not, unless they squarely contact a frame rail.
Unfortunately, we seem to be drifting towards rules makers/advisors who have little to no understanding of these issues.