Chani's narration at the start of Dune 2021 states:
At night fall, the spice harvesters land. The outsiders race against time to avoid the heat of the day. They ravage our land in front of our eyes. Their cruelty to my people is all I've known.
The cruelty of their Harkonnen overlords is undisputed. They place very little value on human life in general. However the spice harvesters appear to leave the deserts in much the same condition as they find them. There is very little life in the open sand areas and the tracks left behind by the harvesters will soon be obliterated by the wind-blown sand. Although the novel mentions areas where the Fremen are cultivating plants and trees, these are in the deep desert. The Harkonnens don't know about them because they are outside the range of the spice harvesters.
The Fremen's antipathy towards the Harkonnens is understandable, but why does Chani say they ravage their lands?