That's because the actor had something else he was going to work on, I think. They just...~rushed Giles,without considering characterization consistency, or even plausability! Like I said, it would have been better if they'd killed or vamped him, to "disappear" Giles, instead of ruining him like that. D:

The show had become the Buffy-Willow-Spike Show, to the detriment of all.