Another way I've seen it handled is that Buffy explains/downplays it, but in those cases Spike generally tells her she's wrong ("you like men who hurt you").

That was the kind of riff I was expecting. Not that his actions were justified but that Buffy forgives him and downplays it. In the Xander case it's often Xander telling Angel and he forgives him quickly. Or the really egregious ones have Buffy beat Xander near to death for it (making her look petty and he look more sympathetic).

Again, it's just "apologist" fic IMO versus accepting the character flaws as intended.