Banning people from participating in politics is a dangerous route. Opening that door would make it possible to ban anyone for any random reason.
The real question is, why do people keep voting for the same parties over and over again? Lots of people complain about their government, yet every time the same parties get elected. It happens basically in every western country.
The same goes for the EU elections. Lots of people disagree with how the EU is developing (as seen by the rejection of the EU Constitution by several countries), but we still ended up having a communist as the president of the European Commission who managed to remove the elected governments of Greece and Italy. Also he didn't care too much about the rejection of the constitution, so he just renamed it, called it the Lisbon Treaty and forced it through anyway.
As long as people keep voting for the same old parties, things won't change.
I think it has something to do with how the media interacts with politicians. During the campaigns you only see the politicians speak about their ideology, but that's not necessarily what they're about to do when they get elected. It would be nice if the media would dig trough the programs and find the hidden caveats instead of hosting those useless show debates. The hidden caveats are usually far more important.
When you're looking for a new TV you can find everything about it easily including independent reviews, but when it comes to something important as voting for your government there's hardly any in-depth information presented at all. Suddenly you'll have to read the fine print in the 300 page manual to find out that the VGA input of your TV doesn't support HD resolutions.