I don't think you can really compare people "jumping down Buffy's throat" and forgiving Faith's murderous ways. Most people in the discussion are just saying that her long speeches got kind of, well, long and annoying. That doesn't have anything to do with her leadership skills. And this is a little bit OT, but Faith paid penance for her actions, and now she's not so murderous. Angel, Spike, Anya, Giles, and Andrew were all forgiven for their "murderous ways", why can't Faith be?
Okay, back on topic now. Yeah, Faith didn't want to be the leader, she didn't ask to be the leader, and she wasn't as good of a leader as Buffy was. But that isn't what this thread is getting at. Most people aren't saying that Buffy was a "pointless biatch", just that she got a little long-winded. And that she actually admitted to thinking that she was better than everyone else. That doesn't make her pointless, just a little conceited.