It means they feel disengaged and even hopeless; if nothing much changes in people's day-to-day life whether they are poor or middle class regardless of who gets voted in, why should they care? If their life slowly gets worse while very few people get richer - again regardless of who is in power - then why would they feel like their vote matters? If voting changes nothing for an individual then why is it their failure rather than the system?
Well if they don't get engaged when they have the biggest stake in change, they have nothing to complain about. If they don't care, why should they expect people who do vote to care about what they want.
Young people who have the greatest stake in change and will inherit the country have the worst voting record. If they want change, get their faces out of their phones (or at least use them to get politicly educated) and do something about it. It takes an hour to vote and they only have to do it four times every four years, once each for federal and provincial elections and twice for civic elections. Four hours out of their lives every four years to partake in a democracy that most of the world's people can only dream about. Poor babies, my heart bleeds for them.