the reasons some say not to eat raw pork is of Trichinellosis, and Pseudorabies
Trichinellosis, also called trichinosis, is caused by eating raw or undercooked meat of animals infected with the larvae of a species of worm called Trichinella. Infection occurs commonly in certain wild carnivorous (meat-eating) animals but may also occur in domestic pigs.
Pseudorabies is a viral disease in swine that is endemic in most parts of the world. It is caused by porcine herpesvirus 1, which is also called pseudorabies virus (PRV) or suid herpesvirus-1 (SHV-1) and is also known as Aujeszky's disease, and in cattle as mad itch. PRV is considered to be the most economically important viral disease of swine in areas where hog cholera has been eradicated.[1] Other domestic and wild mammals, such a cattle, sheep, dogs, raccoons are also susceptible. The disease is usually fatal in these hosts.
I am not sure how much of a risk these diseases pose. I do give my dogs raw pig feet to chew on, I believe it is supposed to be ok if the pork has been frozen. Other than that not eating pork is a religous preference, many religons dont eat pork because it is believed that pigs are dirty animals, since they will eat anything including the waste of other animals.