Hi Swaati,
I read all above mentioned comments, and here my comment goes:
At very first place, if you are working under someone else, really does not mean to tolerate insult. Be professional in this case, your manager is not one to control you. who matters is, your director.
if you think that there was not any confidential matter in a mail, there is no point to create and involved in a war. So be very precise and to the point.
And no need to beg atleast, this is something your manager wants and you do that. You are satisfying her ego. and she enjoys that.
Stop doing this, better you concentrate on your work and avoid her, your colleagues know your work, so do your director. so be happy with that.
Have a meeting with your director, there is noone who can stop you for this. Ask him directly that you would resign if things continue in this way.
You have pretty good experience, field of HR is vast, explore yourself and enjoy your career. do not allow anyone to criticize you.
Regards,
Shreya Parikh
(HR)