Is this a problem?

[cyber-sibes]

I can't open the door unless it's family or friends and when I walk him if anyone even comes in my direction or speaks to me that he doesn't know he growls and lunges towards them. . . . Kujo shows absolutely no aggression at all except when I walk him alone.

please re-read your post - sounds like you DO have a problem, no? Think about what could happen if you're out walking and Kujo decides he'll attack a passer-by, because he thinks he's keeping you safe? Or he decides to chase off another dog? You'll get dragged right along. Can you really guarantee you'll never be in this situation?