Terms of Right or Left, Liberal or Conservative seem to change sides at times. A communist sympathizer in the US is considered a left winger but the same person would be discribed as a conservative by the media if they are from the former Soviet Union. There are other examples of how the terms "Conservative, Moderate and Liberal" or even "Radical" change by the viewpoint of the one speaking.
If a conservative then is one who draws from a traditional basis would any folk song reflecting a sentimental point of view (home, family relationships, friendship etc...) be considered a conservative folksongs.
My friends on the left side of the aisle, please don't think I've just called you a bad name - one should enjoy the spectrum of music and thought without being hung up on labels!