[The Saucepan Man]

As I recall, in UT, the Orcs' ferocity at the Disaster of Gladden Fields and the fact that they did not retreat when charged by Isildur's troops is attributed (in part at least) to the presence of the Ring. The footnote in question suggests that the Ring's effect on the Orcs in this way was a consequence of its (ie the Ring's) intense desire to return to its Master. It provoked in them a subconscious desire to eliminate Isildur and his Men. In effect, it was egging them on.