Advising someone with a fearful or shy dog to expose their dog to whatever induces fear in them, without encouraging owners to have an understanding of thresholds, counter conditioning and desensitization, is IMHO, irresponsible.
Every dog is different and just because someone has had success in improving fear based behaviors with their dog or even a number of dogs, using techniques such as flooding or ‘exposure’, does not mean that it is appropriate for many dogs. Forcing a dog to interact with or experience things that scare it can cause a dog to become more sensitive to their triggers (the things that scare them) increase their level of fear toward them and begin to behave aggressively.
I happen to enjoy swimming, as do many members of my family. The children all learned to swim at young ages and are comfortable and safe in deep water. It would be irresponsible for me to encourage any child or adult, to jump into deep water or dive into ocean waves if I am not familiar with their swimming ability. Neither should I advise a parent to allow their child to be unsupervised around bodies of water until they were certain that their child had the necessary skills to be safe in those situations.
Yet people routinely advise owners of fearful dogs to ignore their dog’s fears and put the dog in situations in which the dog does not have the skills to be safe and comfortable. Their intentions are well-meaning but without seeing a dog, the safest course of action for any owner of a scared dog to take is one which acknowledges the dog’s fears and follows a course of management and training that includes counter conditioning and desensitization. As well-intentioned as givers of this advice may be, they are often not there to pull out both owners and dogs that may find themselves in over their heads and struggling.