That is a very confusing thing to those of us who see "Christians" as a giant homogeneous group.
There's also this idea that even though Christians are in control of just about everything in our country, we still have free speech. Unfortunately (from their perspective), our biggest pop-cultural influences are secular at best and downright anti-Christian at worst. When you watch TV and see casual sex, drug use, violence and other decidedly non-Christian behavior portrayed as no big deal or even encouraged as positive behavior, it's easy to feel like your way of life is under attack. Take a quick look at the TV shows out there (on mainstream TV, not on the Christian channels). There are a handful of shows (7th Heaven, etc) that have a Christian theme. But in most shows and movies any character that's Christian is only there to be an obnoxious zealot and is just a caricature of how most Christians truly act. This, too, causes them to feel under attack.
I think that looking at the entertainment industry as their main source to see how Christianity is portrayed is flawed analysis. You only need to take one look at everything outside of the entertainment industry to see that the points you make are true. But at least it makes a little more sense in this way.