Good afternoon, My condolences on the loss of your dog. Rest assured that the deer are not interested in your dog. This is the peak of the deer mating season. So there are many deer out there with high hormone levels. If the marker was made out of wood, it would have made a very attractive place for bucks to rub their antlers. Antler rubbing can cause a lot of damage.
Additionally, wildlife are curious about changes to their environment. A patch of freshly disturbed soil will be checked out by many species, including deer. Since vegetation hasn't yet grown back, you'll have a good record of what species have been there because the soil will be a good substrate to record tracks.