We are not your friends. We are not your way to Buffy.
But they don't understand. Spike needs a way to Buffy.
Without it, he will go back to the old vampire unlife. Sod the chip, he'll find a way. Not a doubt of it.
Buffy is his translator, evil to good, vampire to humanity. Through her, he reads the world differently to in Spike-view, like a parallel text. He sees why killing isn't always the way, or doesn't have to be, if he chooses. Why the woman on the street corner isn't mere meat. Why fighting the good fight doesn't have to be a joke.
Through Buffy's eyes, Spike sees what he should do instead. What the non-evil thing would be. Sure, he's got it wrong, often, even after he realised Buffy was what he needed. Not always paying attention to his human cipher ring. But he's trying.
Without a way to Buffy, all that understanding ends. Comprehension fails. Killing follows.