IMO the underlying reason for this is one or more of:

1) Americans are [statistically speaking] doing very well, high GDP, lots of consumer products to buy, lots of entertainment, lots of cheap food... and wikileaks is not doing anything to help but maybe destroy this.

2) Americans are also doing very poorly, the bottom 25% have bigger problems to deal with than wikileaks. Why would they care if the CIA is watching them if they can't afford next month's rent?

3) Information overload: Similiar to 1, we get overloaded with things we ought to care about, climate, wiki leaks, wars.... it's too much and people really just want. #1.

Or maybe I'm off...