first of all, there was no blame cast.
second, kwannon was hardly an angel.
but trumping all of that, lets not forget it all became at a certain point a 'retcon' of sorts. A well intentioned move by some at Marvel to make an asian Xman, for a while she was even an amalgam of both women, and for the most part it worked. How many fans of the character were created, and how many cosplayers, etc.
Betsy may have taken liberties in the body, but it was under the impression of the writers that for all intents and purposes, Betsy was forever japanese and thats that. A retcon basically, within marvel parameters.