Brief commentary (relatively speaking anyway) on the article. I disagree with how Xander never lets it go, indeed, he saves her life later with his rival. It's true he hurts and acts inappropriately (just as Willow does when she finds out Xander is with Cordelia). Buffy lashes out when hurt even as an adult, and at least in adulthood I'd say Buffy is worse than Xander in that regard (that's not to say Buffy is bad, just that she's human, and I cut her slack just as I do Xander).
Most of all, a Nice Guy feels entitled to sex just for being nice (that is, manipulative, something of a complex form of prostitution--I've known 2 "Nice Guys" who did say they were just going to have sex with prostitutes when their blatant manipulations weren't working), but when Buffy is completely under his (miscast) spell, he refuses to take advantage of it, because he respects her agency. An entitled Nice Guy would not have let that stop him, and may have even taken vicious satisfaction (as Nice Guys often feel that women "take advantage" of them for not rewarding their "nice" behavior with sex, which generates a lot of anger toward women in general by so-called "Nice Guys"). This is not a defense of Xander blackmailing Amy to cast the spell, mind you, but if he were truly a Nice Guy then he'd have reacted very differently to Buffy throwing herself at him.
He also has ample reason to dislike Angel, at least by season 2, and even then he speaks up in defense of Angel at times. If anything, Xander is more forgiving of him as I would've held a grudge over what Angel pulls in School Hard, and later punching Xander out when pretending to be soulless. (I can understand why Angel dislikes Xander as well, mind you.) I also remember his quote of "The suspense is killing Angel." Xander doesn't like Angel, and Angel doesn't like Xander (and I don't blame either one for their feelings from their respective positions), but both of them do stand up for each other (usually, notable exceptions both ways) when they must, which I compare to how Willow and Anya get along (I completely understand why Willow doesn't like Anya, but she puts that aside as much as she was able).
He is indeed an ass in Dead Man's Party. But so was about everyone else, including Buffy. Ironically, Cordelia was the one to show compassion where the others failed to (though it seems to me Oz and Giles weren't that bad, and got overruled at least once, but I don't want to watch it again to clear up my memory). And they'll all have a turn being asses in other episodes.
And it goes beyond assuming things that aren't actually stated about Xander to twist Xander maliciously telling Riley about Angel's curse. Xander thought Riley knew because Riley said he did, and he knew enough, just not that one detail. Xander was shocked when he realized Buffy had left that part out.
That said, I didn't agree with his Riley speech, and am not a fan of Riley's behavior in season 5. But Xander also said good things to Buffy, including
XANDER: The problem is not you. Don't do this to yourself, please.
BUFFY: It's just ... I just wanna know that there's gonna be another good one. One that I won't chase away.
XANDER: There will be. Promise. He's out there, he could come along any minute.
BUFFY: Yeah, and the minute after that I can terrify him with my alarming strength and remarkable self-involvement.
XANDER: What? I don't think you're like that.
BUFFY: Maybe I could change. You know, I could, I could work harder. I could spend less time slaying, I could laugh at his jokes, I mean, men like that, right, the, the joke-laughing-at?
XANDER: Or maybe you could just be Buffy, he'll see your amazing heart, and he'll fall in love with you.
Buffy looks touched.
BUFFY: Xander, that's ... aw!
She puts her arms around Puffy Xander and rests her head on his big puffy chest.
XANDER: This is the day you choose to hug me? (shakes head, sighs) Buffy?
BUFFY: Mm?
XANDER: You ever think maybe the reason you haven't found a great relationship on the Hellmouth is ... because it's a Hellmouth? Seems to me it's a pretty terrible place to try to build anything.
Buffy closes her eyes looking peaceful.
And
BUFFY: No ... people are the strangest people. (she looks down as Xander continues working) I mean, look at me obsessing about being with someone. It's like ... I don't need a guy right now. I need me. I need to get comfortable being alone with Buffy.
XANDER: Well, I'll say this, she's a pretty cool person to be alone with.
BUFFY: (smiles) Thank you.
As for Anya, the shitty behavior goes both ways. Having Xander explain why the bars work for Anya is an example of that. Anya is such an entitled woman-child who puts her needs before anyone else's at all, and she was just fine with the idea of Xander selling the bars to make money to spend on her, and then not only accepted that, but demanded it. I could probably do an article on what a crappy person Anya is, but I wouldn't want to give the impression I don't like her as a character. I really do like Anya, but I'm not going to smack down Xander without smacking her down as well, when I think Anya was worse to Xander (not for the reason I just gave) than the other way around (though granted Hell's Bells is so hard to watch, and I could say a lot on that that heavily criticizes both characters).
That said, I share Xander's belief that Spike is an evil, soulless thing that should've been dusted long ago, but I do agree that Xander was in the wrong in going after Spike with an axe (and am glad Spike respected Buffy's demand for him to move on, even if she found herself hurt over it when he DID, and many fans hate Spike for one of the rare times he was halfway decent and tried, in his own limited way, to move on as Buffy said rather than trying to force Buffy to see things his way...for that brief moment anyway).
But of course love is like cocaine in the Buffyverse that turns everyone into cranky asses in the need of their next fix (to be fair, it can be like that in this world as well, but it gets tiresome that it seems about EVERY major character is grossly afflicted with it, and even breaking up doesn't seem to cure it, not even years later).
And Xander sees advice from Willow on other girls is wrong when she has a crush on him? How come the author didn't find it wrong that Buffy talked about these things with Xander then? (Even in season 2 Xander comforted her in times, like the time Xander reminded Buffy that Angelus is not the same person.)
After that I I just started skimming, because I was finding the selective tunnel vision about Xander as annoying as she found Xander (assuming that's even possible). And good gods, even taking all of that at face value (overlooking all that is good about Xander to focus only on the bad) makes Xander the worst sort of male to you then you've been very lucky in life.
And I'm tired, so I'll have to stop this for now. I do plan to come back to this thread, and so far I've only given the rest of this thread (since I was on before breakfast) a brief skim, and will likely be replying more.
Xander, along with Spike, tends to be a very divisive character. I guess it just depends on what perspective we choose to see them. 
