Depends on what kind of dog it is. Let's leave exercise and socialization out of it for the sake of argument. There are many breeds that tolerate this kind of cold just fine. Huskies, for example, are perfectly comfortable in this weather. Anybody who argues that 24 degrees is too cold for a husky clearly has not spent much time around them. They LOUNGE in the snow and sleep at this temperature, quite happily.
German Shepherds, labrador retrievers, and other dogs also don't fare too badly in this kind of weather, especially if they have a dog house that isn't drafty.
Short haired or single-coated breeds left out in this weather should be reported immediately. Many jurisdictions have laws that require an owner to bring the dog in if the weather is unsuitable to that particular dog and most of them enforce it. Most if not all jurisdictions also require shelter from the elements, in this case a dog house so they don't sleep on the snow and ice and can get out of the wind.
I find it despicable and it could be the local animal control is under funded or just don't give a crap--this happens, unfortunately. However, usually this kind of thing is more from a lack of reporting because the status quo says "this is okay and normal and acceptable". Nobody feels the need to report it because they think that dogs have fur so they're fine. You'd be surprised how much simple logic eludes people. "You're out in a coat and boots and you're still cold and going in to warm up, your dog isn't any more insulated than you and has to live outside?" Often when it's made that simple many people go "OH CRAP YOU'RE RIGHT!"