The Dwarves are supposed to be honorable to the extreme. Why on earth would they program in loopholes to allow themselves to be corrupted like that? Even ignoring the dangers of outside hostile parties coming in and meddling with their politics (which we know for a fact can happen, because it did on screen), deliberately enabling ways for you to act dishonorably seems like a bad bet, overall.

And now we can stop ignoring the fact that deliberately putting in those loopholes paves the way for hostile outside parties to come in and subvert your politics. The council would basically have to be idiots for those loopholes to stand.