Why do young people oppose him so much?
As a young NJ resident I'd say that most people my age are not particularly informed when it comes to politics (no surprise there) and have trouble separating Chris Christie (R) from the Republican Party in general. They aren't really aware that that are notable differences between, say, Christie and Kelly Ayotte. The term moderate doesn't mean much to them; it's the R and the D that really matters. And they see the Republican Party as Bad, for a few reasons, but overwhelmingly imo because (1) the Reps generally oppose gay marriage, which has unfortunately become for many THE sole issue on which many of my generation judge candidates (and for that matter the only one they know anything about), and (2) because the Reps are often overtly religious, which doesn't play well to a demographic that is largely secular, doesn't really take religion seriously, and often treats it as something distasteful/an object of derision. There's also just the general, thoughtless liberalism that comes with being a college student/recent college graduate and getting most of your news from the Daily Show, Colbert, Slate, Salon, Gawker, etc.
To the comments above, I'd say that yes, gay marriage is a big aspect of the disapproval, but not because young people necessarily are aware of Christie's position on the issue (most of my friends aren't even aware of his veto), but just because he is a Republican, which to their mind means automatically anti gay marriage.
The irony is that many young people who have a kneejerk disapproval of Christie would support him if they actually were aware of his policies, stand on issues, etc. (and, maybe as or more important, the stance of the Jersey Democrats on the same issues).
