‘Moral relativism’ is a term used mostly by by people on the political right. It is meant to convey, most generally, a lack of moral clarity or resoluteness among ‘liberals’ and people of their ilk — if not a lack of actual moral values, period. When it comes to politics, though, people on the right are every bit as morally relativistic as anybody.
The worst of it is not that all people are morally relativistic when it comes to politics. The worst of it is the standard that is used to judge people’s actions.
The only standard that is used by people involved in politics—furthest right, furthest left, and everyone in between — to judge acts of other people involved in politics is the side that the perpetrator is on. If the perpetrator is on the same side as the judger, any act that would normally be condemned will be minimized, or excused, or justified, or, if all else fails, the truth of it simply rejected, regardless of any evidence. If the perpetrator of the exact same act is with the opposition, the judger will pounce upon that person with a righteous fury that is awesome to behold.