Even if you want to look at refusal to go to war as a sign of the true religion (in my opinion it's easier to go that route than to talk them out of the whole idea) there are many other religions that require conscientious objection. Witnesses are NOT the only ones. Here is a partial list:
- Historic Peace Churches (Church of the Brethren, Mennonites, Society of Friends [Quakers])
- Jehovah's Witnesses, of course
- Many Dharmic religions and sects. This group includes Hindus, Buddhists, Jainists, and Sikhs. There are many sects that fit into those religions that are pacifist
- Many other minor sects all over the world
When I pointed these facts out to my mother, she said "Well, that may be true, but only Witnesses refuse to even take part in alternative service!" Chuckling, I told her to go look at the May 1, 1996 Watchtower article "Paying Back Caesar's Things to Caesar" which laid out the new light on alternative service--i.e. that it was okay now. I told her that any Witnesses who went to jail for refusing alternative service had suffered needlessly for a false religious teaching.
And of course I was right--she couldn't argue that one. Yay for being prepared and researching in advance. The Witnesses had some things right. Regular study of the subjects that interest you is one of them.