Anyanka Bunny Slayer
Hail Hydra
Yes. This. Buffy is an adult and she needs to learn how to get on with it. (Also, Giles isn't her Watcher anymore, if I recall correctly) In my experience, constant help just weakens a person. Sooner or later, the training wheels must be removed completely.As people have mentioned. there was a real life reason.
Other than that: I think this is one of the examples where the show's desire to be a metaphor for real life clashes with its internal logic. On the one hand, Buffy is an adult, so she needs to learn to take care of herself. On the other hand, Buffy is a superhero fighting against the Apocalypse and could use all the help she can get.
I love Giles, but he was never the most dependable or caring person in the world. The only person he really cares about is Buffy, and even that is only sometimes. I don't think him moving back to England is out of character.
I think of all the times that he'd mutter something under his breath, in seasons past. You know, rude things...often in response to something Buffy (or the others) said or did. I always assumed it was supposed to be funny, but on second thought, perhaps he was serious. Upon further reflection, I suddenly realise that Giles was kind of a dick. 😂