I apologise if i wasn't very clear about the height of the curb - I meant 20-25cm above the road/track level. The angle relative to the track looks to be about 30-40 degrees, which is fairly steep. If it was vertical, the wheel would be ripped off, no question.
Regarding the BMW video, IIRC when rehersing for the DB9 roll stunt in Casino Royale (James Bond) they were only using a ~30cm high ramp (if that) at about 10 degrees or so. To get it to roll, they turned into the ramp hard to generate lateral-G which makes it much easier to roll. The DB9 has a much lower centre of gravity and is lighter than the BMW, but they still managed to get a roll by exploiting latteral-G.
As another similar example, there are a few videos floating around youtube, where road cars have rolled by hitting a normal curb (12cm or so) at low speeds of around 10-15km/h.
A UK TV show - Fifth Gear I believe - rolled a BMW just by sliding it in the right way on a dry skid-pan.
Bearing in mind the lateral-g involved in the FBM in the replay (curb example only, I havn't seen the other one) of about 2g (twice that of what most road cars can manage), the height and angle of the curb and as such the forces involved, the high-ish ride height of the blackwood setup and the fact that you don't get a huge amount of downforce at ~90km/h, I don't think we can easily say categorically that it would be impossible to roll an FBM in the same circumstances in RL. It may or may not be possible, but IMO it could go either way. Had you steered into the slide, it wouldn't have rolled.
I've also just noticed that at exactly the same time you lifted off the power, the speed of the roll dramatically increased. This could have been caused by a change of engine torque on the chassis and/or changes in rear wheelspeed and/or the rear wheel slipping less and gaining grip. Had you kept on the power it might just have not rolled.
I'm not saying the physics involved in LFS are perfect, but I don't think we can conclude for certain that they are significantly wrong in this case either.