Why does the greature calls the cottagers his "protectors"?

As he tells his story to Victor, the monster admits that he liked to call the De Laceys his "protectors" even though they were unaware of his presence. He says that it was "an innocent, half painful self-deceit" to call them by this name. The irony, of course, is that once the creature is discovered by the De Laceys, Felix attacks him rather than protecting him.