In the Party of One thread, Isuzu said:
So he should have been staked even though they knew he was magically/psychologically compelled to do it? I'm pretty sure that's not how that works. In fact, it's exactly the opposite: it's a way to keep Spike dangerous while absolving him of responsibilities (which is a fact, he didn't do it, the First made him). Meanwhile, Willow killed a man by her own free will. Should she have been staked too?
I also don't really think he really relished Nikki's murder so much as that he disliked Woods (considering said guy is trying to kill him, I kinda see his POV).
Considering that it only took Buffy about two seconds to decide that she had to kill Anya when they found out she was killing again, I'd say yes. Wasn't Anya compelled by her status as a vengeance demon to cause as much mayhem as possible while fulfilling the duties of her office? You'll notice that Buffy wasn't too interested in hearing excuses from Xander about why she should spare her, even though they'd been quasi-friends up to that point. (And even though, unlike Spike, Anya never actively betrayed the gang by teaming up with Adam or threatened to lead a murderous Faith to where she could find them.) The fact is, Anya was a danger to innocent people, and even though I like Anya I can see why Buffy would feel she had to do something about it. She shouldn't be allowed to play favorites just because she played hide-the-salami with Spike a few times, since I'm pretty sure that's not how it works either, and it's an insult to Angel and his struggle to become more in tune with his humanity for her to say "He has a sooouuuulll now" just because she's too chickenshit to do the right thing, even when it hurts.
As for Wood confronting Spike, you'll forgive me if I don't cry a river for the blood-sucking creature that murdered a young mother, leaving her son in the care of strangers, because he wanted to get another Slayer notch on his belt. Having a soul means you're supposed to have empathy and compassion for people (unless something is very very wrong with you) and yet Spike flaunted Nikki's murder in the man's face and said his mother deserved to be killed because she wouldn't give up slaying vampires. Why continue to wear the coat if he wasn't the same sociopathic turd he'd always been?