Not every good idea is an idea that everyone can support. People have moral convictions and they should not be forced to act against their convictions.
Clean needle programs are an empirically successful program for lowering drug rates and breaking up the drug abuse cycle. But a Christian who believes taking drugs is wrong should not have to support the program. Even if drug use drops in the long run, that person’s morals and convictions are violated and they should not have to support or accept the idea.
In Romans 15, Paul writes that those who feel free to do something in the name of God are spiritually free to do so. Those who do not feel free are not free, even if they look over at their brothers and sisters doing these things. This is not to say that they can never do whatever it is. Rather, this means that you have to have a spiritual understanding of some sort that makes the action allowable. It is like an alcoholic with a non-alcoholic friend who orders a beer. The alcoholic does not feel free to order a beer but he might make the excuse to drink because someone else is drinking.
And that is where the sin comes in, because following along without agreeing goes against their conscience. This is also why the inverse is wrong. To try to encourage someone to go against their conscience when they feel it is wrong is itself a sin because you are not helping them to feel that this thing is right, you are only helping them to do this thing. And because they feel that whatever it is is wrong, you are hurting their conscience and testimony by encouraging them to do so.
This is one of the ways in which we can be stumbling blocks to the people around us. Causing them to sin against their conscience and God with our freedom. Now, this is not to say that whoever has the most hangups is justified in expecting everyone to do whatever they want because they are taking the lesser role. By accepting the view of the weaker brother, the person is not claiming themselves to be right but rather to be put at risk by the other person. This dynamic is separate from whoever is actually right and will be approved of by God at the judgment.
That is one reason why I am fond of the phrase to each his own til we reach the Throne. It’s a temporary acceptance of liberality and the marketplace of ideas with the understanding that an absolute authority will one day show the truth.
And that is why a good solution does not have to be universally accepted and it is why we should not try to convince everyone that we are right and that they are wrong. Trying to force other people into accepting our views and solutions is backward because it does nothing to help them see truth and use it in their own lives And we could be very wrong in what we are proposing.
A market place of ideas where different solutions are put to work with honest hearts and good intentions is the better, and I would say more Christian, way of correcting the problems of our society.