In Korea, every eligible man have a obligation to serve in the military for more than 21 months. As one of the Korean man, I also spent some of my lifetime in the military barrack to protect my family members, friends, and any other Korean living in this peninsula from North Korea's vicious potential military aggression.
However, so-called "Conscientious Objectors", which I think are nothing but mean draft dodgers, have refused to serve in the military because of their religious conscience. They always say "We will never pick up any guns and never be trained in the military camp to kill anybody. This mandatory is completely conflicted with our beliefs" and choose to put themselves in jail.
These foolish wusses look only at one side of the shield as if they were born yesterday. These people are usually zealous members of the Jehovah's Witnesses, one of the most conservative denominations of Christianity, which reject to accept blood transfusions and regard any form of governments as Satan's alliance. They even say that they are only the people chosen by the God so that they are real members of the kingdom of the God and therefore all the people on earth are lackeys of Satan except for themselves. Jehovah´s Witnesses sometimes argue that the world will come to end very soon.
Although I'm sick and tired of their apocalyptic warnings of the end of the world, I personally think it is acceptable anyway because this country guarantee us the freedom of religion. The point is that they always keep talking rubbish like a parrot repeatedly.
As far as military service is concerned, Korean government have taken a hard-line stance. The constitution of Korea is severely strict about things relating to national security because the Korean peninsula is still a powder keg and can become a tinderbox someday. It may be no wonder that the second Korean war breaks out now. If Korea is not under the possible attack of North Korea, we can debate on the issue and discern which thing is right and which thing is wrong. However, we aren't currently enjoying an age of peace. That's why I hate the draft dodgers. Freedom isn't free. Some of them claim that without military, peace will come to us, but they must have forgotten about the fall of Daehan Empire(1897~1910) caused by Japanese invasion. The weaker, the more chance of being attacked. To protect ourselves, we should maintain our military.
In conclusion, the debate on alternative military service is superfluous. The Korean war was not ended in a real end but in a truce. No matter how hard members of the Jehovah's Witnesses try to avoid doing military service, there should be no exception as far as national security.