Why did Ponyboy hope Bob's parents hated him and the other greasers in "The Outsiders"?

Ponyboy hoped that Bob's parents hated him and the other greasers because he would rather have their hate than their pity.

After finding Bob's picture in an old school yearbook, Ponyboy starts wondering what he might have been like as a person.  From talking to Randy, he knows that Bob's parents "let him run wild - because they loved him too much or too little".  Thoughts of love lead Ponyboy to thoughts of hate, and he wonders if Bob's parents hate him and the greasers now that he has killed their son.  At first he thinks that if they don't hate him and his bunch, they might pity them, excusing their behavior because of the deprivation and poverty in which they are forced to live.  Ponyboy despises "that pity-the-victims-of-environment junk" because it demeans him and the greasers, he "would much rather have anybody's hate than their pity". 

Ponyboy then considers a third option.  He wonders if maybe, like Cherry Valance, Bob's parents might neither hate nor pity him and his gang.  He wonders if they just might understand (Chapter 11).