I think it is very intentional, I don't think the government wants informed citizens as they are harder to manipulate. I think since the 1970s there has been a concerted effort to dumb down the American electorate. Certainly the Democrats felt they had out of control Hippies who caused the embarrassment of the Chicago riots at the DNC in 1968, I'm sure the Republicans like it very much too given that so many people are so willing to be suckered by FOX, even relatively bright ones.
So I think civics and alot of stuff that was pushed as being patriotic in the time when I grew up fell out of favor because the parties in power probably both felt that an ignorant electorate was a far easier group to rule. I'd like to just blame the Republicans but it just doesn't add up, it benefits both parties equally. Stupid voters, a politicians prayer. Then you can distract them with things like "Obamas a Muslim" it makes their life so much easier in so many ways..
"Our American government; transforming democracy to Idiocracy."
Change you can believe in!