Given that we are discussing political issues I think it can be assumed we are speaking of issues of law: what we should be required, allowed, or forbidden to do. Nor am I referring to the moral justification for government and for laws in general.
What I am trying to address is the all to common habit of claiming that political issues are moral issues with the inevitable result that those holding a particular position are judged to be acting sinfully.
I think this is throwing the baby out with the bathwater. It could very well be true that political issues are, at base, moral issues, but that they are very complex with consequences that are not easy to predict or quantify which is why no one ought to condemn a particular position as sinful or immoral precisely because there is uncertainty all around.
If the consequences were easy to foresee, the morality or immorality of political positions would be clear and determinable.
The problem is that ideologies propose simple and supposedly clear cut solutions which are entirely based upon the ideological presuppositions underpinning the policies. It is those who have proclivities towards ideological views that condemn the other side as immoral or sinful based upon their ideological bias.
A moral realist, at least partially, understands the complexity of the moral landscape and would not so easily side with a particular ideologically based solution.
This is morally wrong and unjustifiable. What is being judged is not the position itself, but the people who hold it, and the judgment is rash and uncharitable. It is the judgment itself that is the fault, not being on this or that side of an issue.
I would agree that condemning others holding a different position is wrong and unjustifiable, but most times that is because those doing the condemning are ideologues who believe themselves to have arrived at the “final solution” and therefore believe their condemning of the opposition is justified.
The reason they think that, is because they have abandoned seeing the issue in all its true complexity and have opted for a simplified view (ideology) that purports to be the only correct one.
The error isn’t one of conflating morality and politics, but of simplifying both based upon a low-resolution, and simplistic view of reality. The reason ideologies are compelling to many is precisely because they are simplistic and susceptible to propagandizing.
‘Punch a Nazi’ is a simple, clear, rallying cry, but is sheer nonsense in its application.