Where is Obama’s big speech on sexism?

I can’t write much at the moment – exams – but it just occurred to me to ask:  Where is Obama’s big speech on sexism?

Why didn’t he give a month ago?  In particular, why didn’t he give it before the DNC made their decision on Florida and Michigan?  Giving it after Hillary bows out will look like what it will be – a naked political attempt to convince her most ardent supporters to turn up on the first Tuesday after the first Monday of November.  If he’d given it two months ago, it would have had at least a chance of being seen as an honest, even gracious attempt to reach out to the Hillary-voters and convince them that he believes in fighting all forms of bigotry.