As a non-rider, I suspect that I am not as familiar with filtering as bikers, though have no problem when it is done properly, (ie undertaking me in my lane on the motorway at 90 is not filtering but suicide!
) I certainly wouldn't expect drivers to know the nuances and might wonder why the rider doesn't move to the front as a pedal cycle would, or as bikes do in London...
As Mr C above states, filtering is analogous to overtaking, it is never a requirement or a right at all costs... and should always be treated with caution, in particular with how it impacts other road users who have possibly made plans based on no bike there and suddenly one appears...
A biker needs to remember also that drivers are not instinctively familiar with bikes, in a car the boundaries of the car are metal sides and mirrors, it is easy to forget that limbs are vulnerably extending outside the bike, especially where they can't be seen...
Therefore I suspect that while the driver was in the wrong in moving forward aggressively, he probably didn't intend to hit her foot, visually it might well have looked as though he was driving alongside her... Also, returning to Mr C's point about overtaking, the biker should have controlled the situation more, setting off more assertively, ready to go as soon as the lights changed, giving the focus no time to move, I suspect that even a moped could out accelerate the focus!
So, focus driver at fault, but situation partially created by the rider who then failed to continue to control the situation... More advanced riding would have factored in dealing with negative responses and avoided the situation, so I think the biker has to take some responsibility for what happened... This isn't car v. bike which many would see it as being, but simply two road users, one doing what was legal but perhaps unexpected, and failing to recognise or manage possible consequences...
Alasdair