I mean, if she had said 'women who voted for Trump voted against their own voice", that would be the most obvious thing ever.
And as much as i am frustrated by it, i even find it reasonable if we're talking about pressuring swing state voters in the general specifically. Even Noam Chomsky admitted that holding your nose and voting for Clinton was really the only option against Trump, if you were in a swing state. Not in a swing state don't bother.
But if we're talking about the primaries and the election itself, that's significantly more problematic of a viewpoint to have and i dont agree period.
Between Trump and Clinton, if you had to vote for one of the two of them, like in the general, then yes, Clinton is the obvious choice. But if Michelle Obama is saying that the entire election, we were wrong to hold primaries and have people challenge Clinton on her weaknesses or even challenge her to be the nominee, then that IMO is wrong, and is not even worth consideration. What's scary about that is this is the view Clinton herself is arguing, that Sanders was wrong to get in the primary and 'harm her', as if she didn't have the same weaknesses that Trump could have exploited without Sanders help.
That is not a valid argument, everything else i'm cool with.