Buffy was actually there to put a sword into Acathala and seal it, not fight Angelus. Of course, she realized that Angelus would have other ideas, and they would have conflict, but Angelus is not the mission so much as the obsticle.
Xander knows this too, he also knows that Willow just got out of a coma and has never done witchcraft before. He also knows that thus far, Buffy's reactions to Angelus have been less than slayeriffic because of her difficulty seperating Angelus from Angel when it comes to beat-downs and slaying, (just like she told giles herself.) He also knows a vamire has killed her before and if not for him she would have died. Like Angel said, he is her white knight...he's always thinking about her. 🙂
So now that Buffy has her fighting spirit again after Angelus takes Giles, is Xander suppose to rip open that old wound and say their is a slim chance Willow can work some magic and get us Angel back, so try not to kill him unless you have to while your playing pin the tail on the Acathala? I don't think thats reasonable, I think thats like asking someone to sign their friends death warrant.
Speaking of death warrants, Buffy 'killed' Angel, not Angelus and to be honest, since that has such high value in this thread 😉 xander never said to kill either one...just kick his ass.
Xander saying kick his ass is not Xander saying Kill him, its simple reasoning...If Buffy seals Acathala and pussyfoots around with Angelus waiting for Angel to get his soul back, she is waisting time that she does not have as well as taking an unecessary risk...one with dire consequinces if things don't pan out.
If she kicks Angelus butt all over the place and drives him away (which can only happen if Angelus is actually afraid she might kill him) or if she slays him, he can no longer pull out the sword and awaken acathala, as well as the added bonus of no longer being a threat to Buffy during the fight.
In Buffy vs. Angelus, Angelus knows the worst Buffy has managed to do to him is knee his growing. In a possible fight to the death, I would favor the person who is actually willing to kill. If Buffy would have held back at all, I think Angelus would have known it. If Buffy pulls a punch or worse yet does not try to follow through with a staking/decapation/whatever, she very well might get killed because someone who fights to win will usually overcome one just putting in their time. If she was fighting to save Angelus' form for Angel to reinhabit, she's not going to dust him and at this point was does Angelus have to loose?
And of course in this fight she did not hold back, because Xander did not give her the hope to fuel that action. If he had I think the fight might have gone differently.
For xander to say what he did for only the reason of jealosy, to make Buffy murder....that goes beyond the moral dilema joss was talking about when he said he wasn't sure that xander did anything wrong. Tricking your friends into murder I'm going to go out on a limb and say is very evil!
I just can't be convinced that is what xander did, let alone his motive for doing so would be so assenine.