The Question and Answer section for Grendel is a great resource to ask questions, find answers, and discuss the novel.
When Grendel first meets Hrothgar's men, he is overcome with curiosity, as are they. If fact, the men believe Grendel to be a tree spirit and attempt to feed him. It isn't until Grendel tries to verbally communicate with the men that they become...
The dragon tells Grendel that he is all knowing and higher evolved than all living things. He believes the theories of humans to be nonsensical, and the Shaper to be no more than a manipulator with impeccable skills in presentation.
The dragon doesn't want Grendel to see humans as individuals. He wants Grendel to continue raiding and killing.... if Grendel starts to see them as something more than inanimate objects, he might begin to think they're important.