As a 'cager' I see nothing wrong with 'lane-spliting' or 'filtering' - providing it is done with care.
In other words, marginally faster than surrounding vehicles.
So, when traffic is at a standstill, bikes should be coming through at a crawl - however, when traffic is heavy but moving at the speed limit (or thereabouts), there really is no need for bikes to be coming through.
I also think that bikers should think very carefully about ploughing through between vehicles (like the above clips) - better to overtake vehicles in the outside lane - since the only place those vehicles would ever think about moving to would be to the inside lane?