Really a lot of the college-age kids are indifferent, especially those not in college, and on both sides. The military ramrods a huge voting effort every Federal cycle, as do all sorts of mostly-pro-Dem organizations on campuses, but even with those efforts, a lot of people in their late teens and early 20s just don't have a set career and unless they are an 'issue voter' (RKBA, Choice/Life, etc.) the tax burden on them is virtually unnoticed, Big Policy is distant and irrelevant to their daily lives on most things, they have no retirement planning to worry about, and they just don't see that they have any skin in the game the same way as their parents do.
They're not entirely wrong. It's all pretty relative.