I support it when there is no alternative and someone is being kept alive mechanically or just existing and waiting for the final hour. That being said it does have to be under a doctor's care. It isn't something very new, nurses and doctors have been practicing merciful deaths for years. No one talks about it, kind of an unwritten code between the family and the doctor. Making sure the patient is pain free sometimes helps the process along, with the family's permission.
I've explained my wishes to my family and they know that under no circumstances should they keep me alive by machines and I also have a DNR in my living will.