In any event in a political discussion political principles can become dogmatic in this example.
Person A) What do you think of the marshall plan,think it will work?
Person B) I oppose it because it goes against non-intervention, and thus the potential net benefit of this plan doesn't matter if it goes against my principle which has no inherent value what so ever....except for the one that i gave it.
on a side note person B formed the argument in a manner that many fundamentalist do. For example fundamentalists often attempt to restrict their opponent to their interpretation of the bible, and this is very similar to how person B tried to restrict person A to B's own principles.( there is a simple trick used in debate to thwart this strategy,but whatever).
In the examples you give, those principles may not be desirable, but in plenty of cases principles are noble, regardless of whether we all agree with them or not. In my case, most of the principles I take the furthest are those having to do with protecting human rights.
For example:
Person A: I oppose gay marriage because I find it repulsive to walk down the street and see two guys hugging.
Me: Regardless of whether you (or most of society) feels that way, the two guys behavior is not objectively harmful to anyone, and they have the right to that behavior and to equality, and our government should prioritize human rights over anyone's perspective of what they find repulsive or not.
