There is no way to know whether Blue understands why someone walked away.
What can be seen is that his facial injury may be creating an impression that does not match the rest of his behavior in that moment.
His Neurological Injury Needs Proper Medical Context
Blue has a neurological facial injury affecting one side of his lip and the normal blinking of one eye.
No additional diagnosis was provided.
The cause of the injury is unknown from the information available here.
It should not be assumed that Blue was hit, abused, attacked, involved in an accident, or suffered any other particular trauma unless medical or intake records confirm it.
There are also important medical questions that need answers.
An eye that does not blink normally may require veterinary monitoring and supportive care because blinking plays an important role in protecting the surface of the eye.
Anyone considering Blue should request his veterinary records and ask what treatment or ongoing care has been recommended.
There is no information here about medications, eye care, pain, prognosis, or whether the facial changes are permanent.
Those facts should come directly from Blue's veterinary team.
His Face Shouldn't Be Used as His Behavioral Assessment
Blue's appearance should not automatically be interpreted in either direction.
It would be wrong to label him aggressive solely because his face resembles a snarl.
It would also be wrong to conclude that he is safe in every situation solely because he brings a tennis ball to visitors.
Blue is an individual dog who needs a complete behavioral assessment.
Potential adopters, fosters, or rescues should ask how he responds to unfamiliar adults, handling, leashing, veterinary procedures, food, toys, and other dogs.
His behavior around cats and children was not provided.
Neither was information about resource guarding or how he behaves outside the kennel.
Those details matter.
The tennis-ball interaction is one positive observable behavior.
It is not a substitute for the shelter's full assessment.
Blue's History Before the Shelter Is Unknown
No information was provided explaining how Blue entered the shelter.
His history before intake is unknown.