Ghost Pokemon in the Anime seem to have to "activate" their intangibility.
Indeed, and it seems to be something some of them don't know how to do (in addition to being trapped in a net we've seen a Misdreavus trapped under a tree).
Even that Dusclops owned by Brandon was effected by the Seismic Toss right up until the last second when it decided to make use of its Ghost type.
Really, throughout the series only the Gengar family has been consistently shown to phase through things like we imagine all the Ghost types can do. And even they have the ability to turn it on and off (i.e. whenever they make physical contact with someone on the show and effect them).
The trouble comes in that the anime only ever explains it in the simple game terms of "normal attacks don't work on Ghost types."
I fully believe that some of these events are simple mistakes on the part of the writers, but to those that balk at solid ghosts, Ghost type pokemon are NOT literal dead spirits, but simply a type of pokemon that can shift their bodies' dimensional planes, enabling their phasing, communication with the dead etc.
Gravy said:
It's like saying Shadow Ball shouldn't be able to do anything to a normal type, despite the fact it's a honking great ball of energy.
Indeed, though to be fair the anime has never said Ghost type moves don't effect Normal types (and I hope it never does as it is one of the type things that makes the least sense to me).
That being said, it wasn't that great of a battle as far as entertainment goes, but then again Jessie was doing the commanding and a poor job of it so what could we expect? At least the stuff occuring outside of the battle was well done enough.
As a last thing, did they really have to choose to have that attack be Thunder? It just looked so incredibly weak compared to any other Thunder in the series that I recall. Even if we assumed the anime decided to incorporate STAB the move still looked way too weak. It might have been acceptable as a Thunderbolt (which as I recall Banette can learn) but not as a Thunder, unless it could be said to have been using some kind of "partial Thunder."