I think this was made so bad more by what by happened outside the show than on the screen.
During S4 before Joss spoke a good deal about the "cliche" and his responsibility to his gay fans, but then seemed to forget it when called on it. People hate that..
Twice in then during season 6 year a Buffy writer told fans Tara would not die (including the writer of the episode, who wrote it).
After the episode the writers were online and on web radio and sounded like jerks.
In the end the writer of the episode SDK went to a fan board and apologized profusely (and to me personally on the Beta Bronze
) and later Joss made his announcement about Tara coming back, but no one had heard of it before.
It was his "I am Spock" moment I think.
Look, he blew it. It happens, he is not a demon or a villain but he was arrogant and deceptive when the writing should have spoken for itself.
When the fans blew up he could have said to the fans "Sorry to have led you on, you are important to us". He could have told his writers to stay of the message boards and try to write better scripts that "doublemeat", but he didn't. He could not have said one single damn word about any of it and let the story tell it self.
My 20/20 hindsight, don't turn Willow into a junkie, write what you want but don't lie to people, and don't put all the energy into the shock value, and none in the follow through (what was the plan, Giles?)
But hey..
First of all, no writer is obliged to fans not to kill off characters, and shouldn't be apologizing for killing off characters.
Second, no writer should have been promising fans anything about not killing off characters. It's supposed to be a freaking surprise when it happens. Writers should not tell fans anything in advance. So, if that's what DeKnight did, it was stupid of him to do it.
Third, if DeKnight said that, he probably wasn't lying, he just didn't know. It wasn't his idea, and he didn't make that kind of decisions. It was Joss's decision.
Fourth, what does Willow's addiction storyline have to do with it? And what does "Doublemeat Palace" have to do with it?!
Fifth, why should a character be protected from being killed off just because they happen to be gay, and how the hell is that supposed to be an argument in favor of gay rights or equality? If you want good gay characters on TV, they should have flaws just like the straight characters (Willow) and can't be sacred cows that are protected from getting killed off or having something bad happen to them.
I suppose someone could also post a rant about Joss killing off Jenny in season 2 and add "and don't make Angel lose his soul after sex [how stupid!] and your tell writers to write better scripts than Some Assembly Required and Reptile Boy!"
^ Joss had very little involvement in the actual production of Buffy Season 6, due to the fact that the production of that season coincided with the development and production of Firefly. As a result, he turned showrunning duties over to Marti Noxon, who was in turn assisted in said duties by David Fury and Jane Espenson. If there was a writer or writers going on the message boards and lying about the possibility of Tara dying, that's something that, utlimately, falls on the head(s) of said writer(s) and on the head(s) of Noxon, Fury, and Espenson, not Joss, which leads into my next point:
That's not true. Joss had LOTS of involvement in Buffy season 6, and even when he wasn't writing scripts, gave notes to writers, occasionally rewrote scripts, and came up with most of the major plot points, including many of the most controversial moments.
Just to name the things we do know for sure (from interviews etc.) that were Joss's idea:
- Willow going dark - which he planned years earlier (even before Tara was introduced; if Seth Green hadn't left the show, then the catalyst would've been something happening to Oz) and which was foreshadowed a lot in
Tough Love in season 5
- Buffy and Spike in a relationship
- Buffy dealing with her dark side (you can see the first foreshadowing of that kind of storyline back in season 2 opener
When She Was Bad, way before Noxon and the other writers who were still involved in the show in season 6 were even hired [Noxon first came onto the show to rework the script for
Halloween and started writing for the show midway through season 2)
- The "Smashed" fight/sex - because Joss insisted that Buffy and Spike getting together had to be something epic and huge; he also chose the music for the scene
- Spike having sex with invisible Buffy in
Gone was something that Noxon said she found "icky" but, according to her, it was something Joss and David Fury came up with and liked
- The infamous balcony scene in
Dead Things was something that "Joss wanted to do for a long time, and it just happened to be in my episode", according to Steven DeKnight. Joss couldn't write any dialogue for that episode because he was busy, but he gave notes to DeKnight that he worked from.
- Joss rewrote the Buffy/Spike scene in
Hell's Bells and made it much warmer, originally as written by Kirshner it was much more unpleasant and antagonistic.
- Killing off Tara. His call, and while he had regrets about it later, he's never tried to argue that it was anyone else's.
From these tidbits, it sure looks like he was more than a little involved. And even those controversial plot points we know he didn't come up with (magic addiction, the attempted rape), he had to greenlight, because he always had the last word, whoever the nominal showrunner of his shows was.
It seems especially odd to try to lay the "blame" (which I put in quotation marks since I love season 6 and don't have any problem with most of the controversial plot points) for the plot points in season 6 on Fury or Espenson, since things would have probably gone much differently if either of those two had been in charge. It's hard to believe that either Fury (who was vehemently opposed to Buffy having any sort of relationship with Spike) or Espenson (who was in favor of a more positive Spuffy relationship and vehemently opposed to the AR, on the grounds that it would make it impossible or too controversial to revive a B/S relationship in season 7) had such big influence on the season as you make it seem.
), which is something he normally never does. Fortunately, he finally decided not to do it. He was probably only tempted because he really loved the character of Tara, and I've heard somewhere that Willow/Tara was based on a couple he knew. 
