How do you know that? It's just a theory that has to be thrown out if evidence turns up isn't it? Or is that why it can't be an ostriche... because then it hurts some other theory?
Or is that why it can't be 165 million years old... because it might be an ostriche??
See... we run into real problems if we promise to throw out theories that are overturned by evidence.... when we find evidence that may overturn the theory. So... no.. it's a bird like, ostriche size, 4 legged but walks on two dinosaur that swims out to sea to feed on carrion.
As for the rest of your ravings, it's bipedal and has a three-toed foot (bird-like features); only two legs left tracks in the sand but all known dinosaurs from this period had four limbs, including the bipedal ones; from the composition of the matrix researchers can determine the type of beach sand and the depth of the footprint gives clues as to the weight of the animal (ostriches mass upwards of 155 kg -- a little on the heavy side for a two-meter long dino, but not out of the ballpark); researchers knew it was swimming (or at least be buoyed up) by the change in the foot area actually forming the track and the depth of the track.
You insist on taking this find and interpreting it alone, rather than interpreting it in the context of all the other evidence from this time period. This is a common creationist mistake, but one they feel comfortable making -- because any piece of evidence can be interpreted any old way when taken only by itself.