Yes, it was bad writing, and an ignominious end to Ash's Kanto campaign. But at least it had a point in what Charizard did, and it served some purpose, making Charizard's redemption in Johto all the more rewarding as well as teaching Ash a key lesson. There was nothing positive in Ash's loss to Cameron.So it's ok because it's OS.....Somehow I am not shocked at all...
EDIT: Whether it was intentional or not, Ritchie being an Ash clone, and for Ash to lose to him in the way it happened, made a point that what caused Ash to lose at I.P. was more or less...himself.