If there is one word that gives me cause to question someone's training credentials it's "Alpha". If I read on a website or hear an individual say to be successful the human needs to become the "Alpha", it tells me that trainer is not up to date on research or on the science of learning. 
That myth has been debunked over and over, yet people still cling to it. There is a place for correct use of the word Alpha. Just not  in describing anything to do with modern dog training.
I don’t expect the average dog owner to spend the time nor thousands of dollars learning about dog behaviour as I did. 
So where does the average person get training information from? Watching TV shows, Google, reading books speaking with family members or neighbours.
Unfortunately, much of the information readily available is based on debunked paradigms and out dated. Yes, even some popular TV shows are based on out dated paradigms. 
You have a choice. You can guide your dog through the ups and downs from puppy through adult, teaching what is expected of him in a humane, common sense manner, following the laws of learning; providing limits, consequences and reinforcement until behaviour is learned. 

Or you can choose to believe going through the door first, eating first, using fear, force or pain is how dogs learn. Some choose to wait for the dog to make a mistake then correct with a harsh physical punishment vs teaching the dog what the correct behaviour is to start with.
Time and time again I witness people jerking leashes, punishing dogs for normal dog behaviour with the expectation the dog will not do it again without ever having taught what is preferred.

Don’t misunderstand me and think there is never punishment. 
There is. 
Punishment, as delivered by myself (I can’t speak for others) is for the most part loss of opportunity; whether to play, eat, be close to a human, go outside, chew a bone, chase a ball, etc.
I have to yet find the need to string up any dog by the collar or slam one down on the floor to show him what I expect.

Dogs do not wake up devising ways to prove they are Alpha. They do, however, try to determine what behaviour they can offer to get what they want in a world where they do not speak the language. Co existence does not have to be based on confrontation.

Results are in. There is more than enough proof of how dogs learn and how behaviour can change by applying humane and effective training methods.

The Dominance Controversy, Dr. Sophia Yin. https://drsophiayin.com/philosophy/dominance/
Dr. L. David Mech talks about the terms "alpha" and "beta" wolves and why they are no longer appropriate.
Pat Miller, CBCC-KA, CPDT-KA,CDBC Whole Dog Journal February 19, 2016 (updated)  De-Bunking the "Alpha Dog" Theory.