语法剖析和句子结构

Youngpeople's disenchantment with the ballot box matters because voting is a habit :those who do not take to it young may never start.

Young people's disenchantment with the ballot box主语 matters不及物动词作谓语 because voting is a habit缘由状语从句 : those who do not take to it young may never start冒号后部分为对voting is a habit的讲解、说明，为补充语。