Some dogs, like some people, are born messed-up, but yeah, cruelty is the most probable explanation, IMO.
One of the rescue dogs (sweet female German Sheppard) my husband got was abused. She would NOT take food from either one of us, even if we dropped it by her and walked away.
It took a while for us to find out what it was. But one day a young Latino male, with a folded-in umbrella approached us. Our dog FREAKED.
We figured that at one time a young Latino male got her to come to him by using food as a lure...then beat the holy pie outta her with the folded up umbrella when she got near.
Dogs don't forget.
It took over a year but she FINALLY got to trust and love us, especially my husband. He SURE had a way with animals.
Poor “parenting”.