Because there are only about 33 million people living in a huge area of 13,100,000 km2. It is very cold in Siberia and the conditions are not good for people's lives, and therefore the population density is only 2,5 inhabitants per square kilometer.
whne your like 30(i think) your not forced but some people still join bc there willing to sacerfice there life to help, if you 18-30 they can force you to join
