Buffy is the Hand. She expresses herself through action. Words, though pretty, can be empty. Someone can apologize but it doesn't mean a damn because they're just words and what if their actions contradict their pretty platitudes? Instead of voicing guilt (something I believe the audience needs more than the characters), she offers acceptance and support. And she risks herself for Spike's sake. This is a lesson Buffy learned from being the Slayer--you show your love through your actions. You sacrifice yourself for those you love, you put yourself in danger for those you love, you protect those you love. That is love.
So when fans demand she apologize to Spike, I feel it's more what the fans need. What Spike needed was forgiveness, support, and the ability to believe he could be more. Buffy gave Spike what he needed, not what the fans wanted.
An admission of guilt is often brought forth by the confessor's need to alleviate his or her own pain. Tortured by these thoughts, they voice their guilt to win absolution and forgiveness. Has anyone then considered that Buffy doesn't voice her guilt because she accepts her fault and doesn't want to lay this weight on someone else? That she views asking for forgiveness as a selfish act, one that she doesn't deserve?
BUFFY: It is! It's wrong. I'm wrong. Tell me that I'm wrong, please...
Buffy starts to cry for real now.
BUFFY: Please don't forgive me, please... (sobbing) Please don't...
She slides off the table onto the floor, kneeling, putting her head in Tara's lap. Tara looks uncertain, puts her hands comfortingly on Buffy's head.
BUFFY: (sobbing, muffled) Please don't forgive me...
She feels she must carry this burden of imperfection. She was wrong. When Buffy's finally in a position to come to terms with what she's done in Season 7, it would be selfish to go to a mentally unstable and morally tortured Spike, to lean on him and ask him for forgiveness. Instead of voicing her own turmoil, she works to save him, to help him. It's the actions of a person who doesn't believe they should be forgiven, sadly. That another's pain is more important than her own. That she caused them pain and shouldn't be demanding they alleviate her own.
Buffy: He wants forgiveness.
Giles: Yes. I imagine he does. But when James possesses people, they act out exactly what happened that night. So he's experiencing a form of purgatory instead. I mean, he's, he's doomed to, to kill his Ms. Newman over and over and over again, and... forgiveness is impossible.
Buffy: Good. He doesn't deserve it.
Giles: To forgive is an act of compassion, Buffy. It's, it's not done because people deserve it. It's done because they need it.
Buffy: No. James destroyed the one person he loved the most in a moment of blind passion. And that's not something you forgive. No matter why he did what he did. And no matter if he knows now that it was wrong and selfish and stupid, it is just something he's gonna have to live with.
Buffy doesn't believe she deserves forgiveness. Forgiveness would end her suffering. Instead of seeking forgiveness, she makes amends. She helps Spike to heal, protects him, saves him. Instead of helping herself, she helps him.
Later, when the spirits have been freed...
Giles: Well... they can both rest now.
Buffy: I still... A part of me just doesn't understand why she would forgive him.
Giles: Does it matter?
Buffy: No. I guess not.
She shall look on him with forgiveness, and everybody will forgive and love. He will be loved.
So everything's OK, right? (sighs)
Can—can we rest now? Buffy...can we rest?
"Can we rest now, Buffy?" then becomes code for "Have we forgiven each other?" The haunted spirits in I Only Have Eyes For You were only able to rest once they'd forgiven each other. Spike wonders if he and Buffy can rest. If everyone will be forgiven. By making amends, Buffy finds herself forgiven just as she forgives Spike. And soon Buffy will rest in his arms. In Touched, in Chosen, they will rest in each other's arms. They rest. They forgive. They are at peace with each other. And everybody will forgive and love. He will be loved.
So I wonder then why people continue to wait for Buffy's words. Why are her words worth more than her actions? It is her actions that speak louder than mere words. In the show I was watching, Buffy and Spike forgave each other. And it was beautiful.