Simply because they pursue their interests. And we all do.
The issue is with the public that elects dirty politicians, not politicians themselves. Politicians suck because voters suck. That is why I haven’t voted for 10 years now, and ain’t planning to do so in future.
“What about the civil duty?” – one might ask. “How can you hope to change the country if you don’t participate in the election process?” Bla-bla-bla.
To this I will reply: “Cut the bullocks, will you?”. Thinking that representative democracy gives a freedom of choice is the biggest illusion of all. There is no bloody choice. At least in the times we’re living in. The only choice you get is between Pepsi and Coca-Cola. Feel the difference?
By the way, states are not run by politicians. Surprise-surprise? Well, formally they are, but in truth politicians decide very few things. Check out Colin Crouch’s book Post-Democracy for some insights here.
Democracy is dead. Democracy, at least in the form that we witness today, is manipulation of minority over majority in order to pursue its (minority’s) interests.
Let me conclude on this. Political elites are always a reflection of the society they represent. Every nations deserves its political establishment. So in order to change the country you live in, there’s no need or sense in voting for another democratic ass-jack.
All you need is change yourself.