I've seen references to her truth quite often in her speeches and in her book quotes.
I think the clue to the comparison is in the italicised word expectations in the OP. Well, that's how I saw it anyway. In a FLOTUS/Royal role there are, rightly or wrongly, assumptions that a spouse will behave in a particular manner. Michelle = Meghan in this respect. Neither has to, neither chooses to, good for both of them. Colour is irrelevant.
I never usually get involved in arguments about racism on GN, (ever since I was accused of being racist by saying ScoobyDo instead of Omid Scobie!! Stupid made up comment!!). What I was irritated by here today was the insulting tone of shame on you as an insulting remark when we really don't know.