Are political campaigns unfair to women? Probably. There are many, many reasons why electing Hillary Clinton president would be a bad idea, but the fact that she looks her age isn’t one of them.
[Update a few minutes later]
I guess other people have to be wondering, though, if this haggard look is the result of a campaign (and one that is still in a primary, having not even gotten to the general), what would she look like after four years of the presidency? Will she even survive a general campaign? I recall being shocked in 1980 at how much Jimmy Carter appeared to have aged in his term.