The question is biassed 🙂
I don't think there's anything inherently powerful or interesting about those relationships. It's the hardcore fans that make them special for themselves with wish-fulfilling fan fiction, "head-canons", fantasies, absolutely ridiculous whitewashing of the characters and over-identification with them.
What's with the dichotomy? A lot of people simply do not care, ignore, like the show despite etc.
Spike and Angel are not men, and I'm not even talking about the inhuman reanimated corpse monstrosity factor this time. In their relationships with Buffy they are merely walking fantasies designed for infantile females, eternal teenagers with no sense of responsibility, no personality, no purpose, no hopes and no dreams unrelated to loving their precious, perfect princess. One could say that *puts on shades* they have no life.
It's not that they aren't real, it's that they are fake.
Preposterous, it's time wasted between funny puns and rocket launchers. I do admit though that I do enjoy those rare, precious moments when the show goes into self-parody mode and makes fun of Angel and Buffy. Sadly, Buffy and Spike is treated in a dead serious, no fun allowed manner.
Ordinarily, when I disagree with someone over something, it's a good thing. I have fun debating differences of opinion. However, in this instance, I don't understand the need to get personal, or quite frankly, a little bit insulting. Of course people who are into the relationships between Buffy, Angel and Spike make them "special for themselves". In what form of entertainment, television, books, sports, anything, doesn't that apply? It's a matter of personal opinion, which is why people emotionally invest in fiction.
I like hearing different opinions from mine, but yours is worth no more than mine, just as mine is worth no more than yours, so accusing me of things like "wish-fulfilling fan fiction and over-identification with them", and belittling me (and anyone else) for liking those relationships and identifying with them is, honestly, just rude. I enjoy debating with you (as I've done in previous threads) about Buffy, but it doesn't become fun for me when the conversation devolves into insults. That's not why I come here. Do I wish that I could find someone like Buffy in my life, and do I try and take the best parts of Buffy and Angel and model myself after them? Hell yes I do. Sue me. If that makes me an "eternal teenager with no sense of responsibility, no personality, no purpose, no hopes and no dreams unrelated to loving their precious, perfect princess" in your eyes, fine. Frankly, I'm sick of defending of myself for feeling that way.
Moving back to the question that this thread is supposed to be about, I think you're just flat out wrong. Saying that Angel has no sense of responsibility or personality is, as you would say, preposterous. I can see where you're coming from one one or two points, but responsibility is a major theme of Angel's character, during his relationship with Buffy and after it. Finding a sense of purpose is one of the central parts of Angel's character arc beyond Buffy (granted, it does develop more after he leaves Sunnydale). I mean, did you even see "I will remember you"? He gives up a perfect life with Buffy because it would cost others their lives (and also, I will admit, to save Buffy). That's not maintaining a sense of purpose?
I have a tougher time defending Spike, but with Angel I don't think you could be further from the point the show is trying to get across. I don't think that weakens Spike's character though. Spike is different than Angel. His relationship with Buffy is different than Angel's. Sure, I like Angel and Buffy more, and I (*Gasp!*) identify with them more (a lot actually), but that doesn't mean I don't enjoy Spike's arc with Buffy as well. I did find it interesting. Spike has an entirely different arc than Angel does, with Buffy and without.