From now on, at least, they should be. Storage is relatively cheap and the shows can be monetized in other ways to help fund new productions.
What would not be acceptable would be to delete original content that has already been created because it's unsuitable for modern sensitivities. The best approach could be to offer the adaptation and have an option to watch the potentially upsetting content. I think broadcasting content that, for instance, promotes racism, homophobia, or misogyny, violates the BBC's mandate "to act in the public interest". OTOH, pretending it never existed also goes against that mandate.
What would not be acceptable would be to delete original content that has already been created because it's unsuitable for modern sensitivities. The best approach could be to offer the adaptation and have an option to watch the potentially upsetting content. I think broadcasting content that, for instance, promotes racism, homophobia, or misogyny, violates the BBC's mandate "to act in the public interest". OTOH, pretending it never existed also goes against that mandate.