Probably. But, in defence of the driver, before the last brake check the biker had accelerated away hard...if I'd been the car driver I'd have thought he was on his way...and would not have expected the violent braking.
That's a very (the) significant point so far as the collision is concerned and one which would, in my view, have found much sympathy in court.
Although there are very few accidents in which 100% blame can be laid at the door of one or the other driver, a split liability decision by a civil court may well have decided that the biker was largely to blame for the collision and would therefore have awarded the far greater percentage of blame to him - in my opinion.