Contact is not justification for a DQ, otherwise that whole field would have been DQ'd.
A. Passing someone on the inside is an absolutely acceptable way to pass someone. I've done it a hundred times, and it never happens to me. Why? Because I F@#ing run on the rail and if someone else is trying to block a pass by running on the outside of one then they deserve to get passed on the inside
B. Burka tryed to cut her off, initiating the contact. It was a desperate surge by someone who knows they are going to get passed. I've also done this type of surge often; although as previously noted, I can't cut them off because I'm inside of them.
C. When you make that type of surge, you are DYING, and have very, very little control over your balance. I've come very close to tripping on blowups like this many times, of course no one has ever made contact with me when it happened, or I would have fallen.
D. Weighing 80 lbs and being off balance means you will probably fall with contact. Live with it, its one of the disadvantages of being small. Much more contact was made by the Russian halfway through the race, I didn't see her get DQ'd.
I say all of this as an American who was rooting for Rowbury, Willard, and Thomas over everybody else and who didn't care about anybody else's finishing place before the race. This was just a bad, political call, and the reason I most love this sport was supposed to be its freedom of these type of things.
And to top it all off, I've fallen with 180 meters to go within stiking distance of the lead because someone else tripped me in what to me, at the time, was by far the biggest race of my life, so I know that DQ'ing someone that the event officials decided started the mess doesn't make you feel a damn bit better.