It's very funny, because that's exactly how I invisage politics working (I'm a bit of cynic when it comes to these things).
So, does it do us all a disservice?
I don't think so. OK, being a comedy, it may exagerate it to an extent, but you can't argue that spin and working the media are one of the biggest parts of politics today due to the way our society works and it's good to have this fact waved under our noses occasionally.
The most important thing to most politicians appear to be their careers, what they need to further them is votes and how they get them all depends on public appearance. Given how important the media is in modern society it is natural that spin to show political parties in the best possible light should rule.
Some of the best comedies are funny, exactly because there is an element of truth behind what they are saying and from what I can see the same is true here.