Politicans - policies= rules, legalism. Some Christians are really into legalism, some aren't so much and believe grace can carry us through.
Some people want to make all the rules.
Personally I think rules need to be guidelines and yes it is a hassle making sure everyone follows them. But they are only schoolmasters to bring us to Christ. They are not the thing itself. If everyone was a Christian, we would have it all written on our hearts and we could trust that we can do the right thing. But for many people they don't know these unspoken rules until someone has a big debate in parliament about them, and the Acts or legislation gets changed. Bylaws and rules tend to change all the time too, which can be unsettling for people, and when you've followed one rule and it suddenly changes or you've been law abiding all your life but the politicians bend or flout them, or completely change them, you're never certain of anything.
Running or governing or adminstering a country can be a minefield. Obviously everyone is different and geographically diverse, but you want to do the best for everyone. In the end no matter what party you subscribe to, we are all humans.
We are flesh and blood and don't always do things right. So I guess thats why we need...politicians. Otherwise it's complete anarchy, right? That can be a good thing or bad depending on how much you like law and order lol.