Participate in Election, Right or duty ?

Almost state in world apply Democrate. Indonesia also apply democrate goverment system. It has meaning thatstate guarantees of human right. One of human right is freedom to pick and choose. It has been set in law. Goverment promises to ensure this human right.
For another state in the world maybe there is state which compulsory their citizen to pasticipate in election. Moreover this duty is setted in their law. But, then they remove it. Because, they dont apply in fact. So, it appears a questions. Why we must participate in election? They answer that this rule is to create a legitimate goverment. This duty is mentioned " Compulsory Voting ".
But in my opinion, this duty is not match with freedom of pick and choose. This duty will exactly destroyed politic. Because of there is a compulsory unsure. It makes many sound paper are invalid. It also makes increasing random votes (the meaning is random in selection ). Finally it produces strength goverment, but produces doubt legitimate of goverment. Because the political parties in election is a right each person. Moreover if someone select become "netral" it is a right too. So we are not compulsory to select in election. Maybe they have areason, why they become a netral. For example no politic parties is necessary with her/him heart. It will be better if election produces in fact citizen selected. Than all people select in pemilu but it produces goverment which win by lucky.