That's a terrible attitude
and a terrible assessment. Obviously some vote for what will help them the most, but others vote based on principles they believe in. Your concept is that someone who drinks and drives will prefer to vote for anyone running who wants to reduce penalties for doing such. Anyone who is sexually lose and morally bankrupt will prefer to vote for those who are the same. As for the latter, I will agree that seems to be the trend in today's world. Yet, unlike you, I'd like to think most vote for what they consider principles, even if it may inconvenience them at times when such are applied in a legal sense.