Take a deep breath, and decide to visit him, sans dogs, one day. Bring him some, I dunno, a bread, flowers from the yard, or a casserole or something, just an excuse to say - "We're neighbors, I feel we've gotten off on the wrong foot, and I wanted to re-introduce myself." If he is just lonely, and has nothing to do, you might find that out. After some non-dog-related conversation, hopefully, you could ask him if he ever had pets. Maybe find out if he just hates animals and why ... Ask him how long he's been in the neighborhood, who lived there before ...

Maybe you could reach him somehow. Maybe, best case scenario, he IS just lonely. If he's never had pets, ask if you can visit again and bring you sweetest politest "dog ambassador" - but not one of the Danes - the sheer size intimidates people, and they don't know it's just a big marshmallow in a dog suit! Anyway, maybe you can rehabilitate the relationship?

In Pettalkville, of course, he would become a volunteer dog walker ... instead of a dog-tattler!