Can you explain the significance of this quote from Chapter 21 of Wuthering Heights?
"I began to dislike, more than to compassionate Linton, and to excuse his father, in some measure, for holding him so cheap."
Note that this is a comment made by Nelly Dean to Lockwood as she narrates the past events that have led up to the present. This comment describes the gradual change in her feelings towards Linton, Heathcliff's son, as she observes his true character. Note what has led to this comment. Nelly is watching Linton and his cousin, the younger Catherine, chattering together and making fun of Hareton and of his rude and ignorant nature. Note what Nelly tells us about them:
...the boy finding animation enough while discussing Hareton's faults and deficiencies, and relating anecdotes of his goings on; and the girl relishing his pert and spiteful sayings, without considering the ill-nature they evinced.
Thus Nelly, although initially feeling sympathy for the sick and ailing Linton, begins to feel less compassion for him as she discovers more about his true spiteful nature that enjoys taunting and making fun of those that he considers to be beneath him in social standing. Let us remember that Hareton actually comes from the same social background as Linton, but has been reduced to his present state because of Heathcliff and his desire to gain his revenge over Hindley by doing to his son what Hindley had done to him. It is therefore wrong to mock Hareton for deficiencies that he cannot be blamed for.