Dunno, I'm tempted to say that, unless you're making a film about naturists, then most nudity and all sex scenes are pretty much gratuitous. But being asexual, I would say that, I suppose.

As to why make the film - these are things that happened, and those are the people who were involved. The events were momentous, the people complicated. A history book will never put these across to non-studious types, but a well-made film of TV programme can. But it is not for the writer or film-maker to make moral judgements, it is for the consumer. Also - and this has been said time and again - the context of the times in which the events took place must be considered. We know more now than they did then, after all, and notions of right and wrong have changed and are changing.