"You call it holding a grudge, I call it having boundaries" 

One of the consequences of doing shitty things to people, is that they might not want anything to do with you anymore. Doesn't mean they're mad, bitter or "holding a grudge" (although I don't blame them), they just want to create boundaries, perhaps to heal from the damage you've caused? To protect themselves? To live a happy life? 

They're doing the opposite of "holding a grudge" and have moved on, just not in a way that's convenient to you because they haven't forgotten what you've done. Your real issue is with the boundaries they've put in place, which mean you can no longer take advantage of them. Their boundaries are a reminder of the things you've done and you can't deal with it. So you try and dismiss their boundaries and what you've done, by saying they "hold a grudge".