The horse moved out of his lane and interfered with another horse. If you look at the tape, its not even close. So what do you suggest the Steward shouldve done?
Let it go....the declared winner was never impeded in the original contact as the commentators stated....19 horse field on a sloppy track is gonna be rough.
Look at the results. No horse was really impeded and kept their pace. They were all running in their lanes basically head to head in the stretch. The best horse won.