So if there's less ice, it's because of global warming. But if there's more ice, it's because of global warming.
Yes. There is less ice in some areas due to global warming and more ice in other areas due to global warming.
Think of it this way: Imagine the entire planet heated up by 20C, we wouldn't expect to see any permanent ice outside of Antarctica. (The North Pole might get some seasonal ice, but the much warmer oceans would melt it fairly quickly.) Now, with all of the oceans that much warmer, think how much additional water vapor would make it into the atmosphere. When the additional water vapor ends up over the South Pole, it will be cold enough for it to freeze and fall as snow. As the snow accumulates, it compacts into ice and we end up with a LOT more ice at the South Pole.
So: Less ice everywhere but Antarctica due to global warming, but a lot more ice in Antarctica due to global warming.
(And, yes; I do realize that this example is a vast simplification - and overstatement - I just used it to illustrate the point.)