The point about language is to comunicate what it is you wish to say. The rules of grammar should help towards this end - and if they are outdated and do not help towards this end - it is of no practical use to be a slave to them or abide rigidly to them.

It just takes a little bit of extra thought to ensure that the words you are choosing are saying exactly what you wish to say.

And as it is so easy to find non-gender specific words - it is probably now safe for the reader to assume that when a writer has chosen to use one that is gender-specific - that is their intention.

When a man calls another man a bitch - there is usually a reason for this choice of word.