well, I don't think it does really: pragmatism implies taking a stance based not on morals but on how you see the world as it is rather than as you would like it to be. Pragmatists would say, 'The truth is that some people are slaves, and they are cheaper than hiring staff and paying them a decent wage, so I will use them because I will be able to produce my cotton more cheaply and so make more profit.'
(But of course you could also have a moral view that slavery was fine - some devout Christians had slaves, which we would now think outrageous. But I would still call them pragmatists, although the question of whether slavery was 'right' is not one pragmatists would bother with.)
Just to use a more modern example: the USA is worried that countries like Iran and North Korea are trying to develop nuclear weapons. They are threatening Iran with unspecified retaliation but are taking a much less confrontational line with Korea. Why? Because they think starting another war in the Gulf would not add greatly to the upheavals already going on there but starting one in East Asia could set off a huge conflagration - possibly drawing China in on North Korea's side; and the Americans are scared of China.
So they're not taking a moral or idealistic line - which would suggest that all countries are equally right, or equally wrong, in seeking nuclear arms and should be treated equally. They're taking a pragmatic line, which suggests they think they can get away with threatening Iran, but not with threatening Korea.
'The truth' is what they base their actions on: the fact (or in this case the strong suspicion) that these two countries are indeed planning to go nuclear. 'Pragmatism' is how I would describe their response.