One caveat I’m Canadian, not American, although to anyone outside of North America that designation is unnecessary and Canadian should likely read “American who gets more snow”.
However I am also one of those young adults in university who chooses not to vote (which irritates some associates, as I’m in the political science faculty)
This is not through ignorance; I spend enough time reading to know the issues and to come to an opinion on them. I can’t obviously speak for everyone, but most of my friends (an admittedly small subsection of society) do keep up with the days events and can discuss politics at some level.
I think it breaks down to one major issue, and one minor one.
The first is apathy
It’s exceedingly prevalent and it’s not something easily fixed. Part of is a loss of trust and faith, in part because of what Kizarvexius mentioned, part of it is isolation from the current political parties. The article brings this up somewhat when it mentions
“The greatest differences among the two groups appear to be on social issues, especially gay marriage and ethnic diversity.”
It’s not in a political party’s interest to offend voters, and when you have a large relatively homogenous body that has historically supported your party and currently is supplying your party with funding through generous donations, it makes sense to sway in there direction.
A specific example of this can be seen in Canada (and its likely to be similar in the States) our rightwing party is referred to as the “Alliance” (ignoring current merger concerns, as well as the PC which at the moment is atrophied) which if you prefer you can read as “Republican” as most (though not all) of their stances on issues are similar.
In general they tend to be fiscally conservative and socially conservative, but this does not line up well with most 18-30 voters, who tend to when being fiscally conservative, often very socially liberal. Because the beliefs of the 18-30 voters do not fit as neatly on the Right-Left spectrum it leads to a feeling of being lost, as they support neither of the major parties positions in area’s they feel strongly about, leading to the feeling that both major parties are invalid.
The good news is this will fix itself, boomers are dieing, younger persons are reaching the age of majority, the tide eventually shifts and for a party to remain relevant it must adapt to the new belief values of the “norm” of society. So 10-15 years or so down the road, probably those who are currently apathetic will be involved, and we can ask the question of why the new younger generation is so apathetic and scratch our heads in wonderment.