Alpha/beta paradigm is not a real thing in wolves, which is where the concept comes from. The researcher who originally created the terminology later found with observation that it was flawed, and other researchers who attempted to confirm the alpha/beta model found no evidence for it. It's unfortunate that it has spread into the zeitgeist and is accepted as a universal fact by bullies with very little knowledge of actual animal behavior. Dogs don't listen for tone other than whatever tone you repeat to them when rewarding behavior (or punishing behavior if you're a bad person). If you watch the follow-up, the dog becomes very well behaved and listens specifically for what you think of as a 'beta' voice. If your dogs respond to a low demanding voice, that is because you have specifically trained them to do that. Most of us would prefer to speak to our pets like people, with kindness and encouragement.

I agree. The dog seems very aloof and disinterested in these people. There are unfortunately so many dogs in shelters that would literally have been falling all over these people for attention and affection, it's too bad they didn't adopt one of those.