Leaving a dog outside a shop

Hi, I was just wondering what people thought of a situation I was in earlier today.

I was on my way home from work and saw a dog tied up on a lead outside my local shop, I didn't really think much of it as it is quite a normal thing to see. I then went into my flat and about half an hour later I looked out of my window and the dog was still there! So I waited another 10 minutes and the owner still hadn't returned so I went in to the shops to ask if anyone had seen the owner, they had not, I then went to the next shop and the owner pointed at a man who was crossing the road. I went out and spoke to said man and mentioned that the dog had been left outside in the wind, rain and cold for a long time, he then tried to argue that it was a collie cross (much like my dog who sadly passed away a couple of months ago) and they are sheep dogs and that famers leave them outside for a long time in these conditions and then went on to say that if it was a baby he would have done the same thing! He also said that he had been confronted before about leaving his dog outside in the rain. I understand leaving a dog outside a shop for 5 minutes while you grab a pint of milk or a newspaper but 45 minutes is a long time! I tried to explain that people steal dogs (a dog was taken from outside a house just down the road a week ago) and that clearly she wasn't happy about being left as she was pining and shivering. She was also tied up extremely close to the road and was sitting on the kerb! This man had clearly been drinking and he went off down the road unable to walk in a straight line. Was I wrong to be concerned/'interfere' (as he put it)?