Why dosent the dog just move away?

https://www.facebook.com/photo.php?v=10152936315227506
In a group I am in people are chatting about this video (sorry Im not sure how to put it up here so just click the link)

It is a confusing video, to start with it looks like the dog is really enjoying licking the baby, when the baby moves there are loads of signs from the dog that he is not wanting the baby there, leaning away, ears back, whale eye etc
But the argument most people use is that the dog must be happy because there is nothing stopping him moving away

This really got me thinking
I often say to Ben 'you can just move away' when a male dog gets a little over friendly with him, even if the other dog is on the lead Ben will not just move away, instead he will start giving out warnings. I try and step in before this point but sometimes Im not quick enough and he starts freezing, whale eye, lip wrinkles, growls and sometimes even a air snap

I actually dont think dogs see an option to move away - all their signs is to tell the other dog/animal to move away
The only time I can think of I have seen a dog move away is actually in fear (and even then only some dogs move away due to fear, many more try and make the other thing go away)
Its almost like moving away is an apology so the dog being 'wronged' is not going to say sorry, he is going to make the other dog (baby) do that

So please do not assume your dog is OK with something because they havent chose to move away - perhaps they dont see the option of actually moving away