Politics is a game of making coalitions. People may be in favor of a law for disparate reasons. Take a law against prostitition. One person may be in favor of it to reduce trafficking. Another to reduce premarital sex. A third to reduce husbands' opportunities to cheat. A fourth to reduce the spread of std's.
On the other side there may be one person that wants to have sex with prostitutes himself, another that believes women should be able to do what they want with their bodies, a third that believes prostitutes can be an important way for young men to gain sexual experience and skill, a fourth that thinks prostitution is bad but legalization to be a way of harm reduction.
Not all of these people may be willing to admit their reasoning in writing. You could say that only following the written down reasoning is a feature. I haven't thought a lot about that subject, so I haven't made up my mind on it.