Honestly, you need to take your "expert analysis" and shove it.
No matter the size of the thief, he now wants to exit the premises. Stopping to fight only escalates his chances of getting caught by responding security.
OP, I believe your story, with the possible exception that you maybe downplayed the tenor of your responses to the investigating officers.
Once you get on their wrong side, it's all downhill from there. Sorry, but that's just the way it goes. This goes double and triple when you are being questioned by a potential asshole.
You suck it up, never ever get off on any "why are you talking to me that way" tangent, as it will never end in your favor. Unfair? Yes, but life is often unfair, and you have to work within what you're given.
The more he's an asshole, the more you have to "yes, sir" and "no, sir" him to assuage his need to be in control, which even a good cop is trained to seize. Just the way this works.
I gave an opinion, now here's an expert analysis.
Problems with the story.
The chances a guy has an electronic key that will unlock the door without being logged is impossible. Every key should have an id. (This I can confirm with no problem, my brother in law works security in AC and has for years, I will ask him.) The locksmith recorded his buddy's key but no one else's. So we know the door was working. So unless you believe the locksmith is on it, we know he has no reason to lie. The act is one of a more hostile robber, but the behavior is that of a petty thief. They don't match. A petty thief will try to rob someone and if challenged, run away, but not to the point they are going in 4 and 5 star hotels at 3:30 in the morning.
Now a more hostile robber would, but he is not going to run down a hall with some person chasing him. No, in AC if one those boys breaks in he will more than likely have a gun or some weapon and he ain't running. More problems with his story. I know from the countless times I have been in AC, a disturbance like what he is describing will have someone call the front desk to report it or someone will literally open their door to look at what is going on. Kinda funny neither of those things happened.
More issues. There is housekeeping, janitors, and room service people all night long, but in all this "commotion" not even any of those folks came across any 6'3-6'6 black linebackers roaming the halls. But yet he is chasing some guy for 7-10 minutes and no one heard or seen anything. Not likely. Especially if the guy is screaming in the hall as he claims.
Add to that, where did he go? He didn't leave obviously.
More problems. Neither guy was drunk, thats a problem, a huge problem. Why? Because here is his story. He sees a shadow of a head, but couldn't tell if it was his friend, but when the cop questioned him about how could he not know if his friend was in the other bed, he said the lights were out. Hmmmm its to dark for you to recognize your friend who is white in the dark, but you can recognize a large black man in the dark. Also why did his friend not wake up in the midst of being hollered for and the supposed "commotion"? He claims he had only one beer.
So while its not totally impossible, if I was the police I would dismiss the guy too.
What I believed happened was his friend was still out, brought one of those nice girls you see all night long in the casino back to the room at 3:45 am. His buddy gets distracted, probably a little tipsy, goes to relieve himself and the sweet looking trick lifted his wallet. His friend wakes him up and they concocted this elaborate story so they can hold the hotel responsible.
One more thing, if the large black man asked for the phone and wallet and both of them were right there, why didn't he take the phone also?