I usually think of "slut shaming" more in terms of treating girls who sleep around as sluts but not holding men to the same standard, though I suppose it has various meanings.
To me, casually "sleeping around" (presumably while single) is different than "cheating" on a long term partner with a married man.
That said, Rupert is even creepier in my opinion and should be more ashamed and shamed because he's the married one, he has children, he was essentially Kristen's boss, and he is twice her age. He should be the most a/shamed of the bunch.
Kristen is a bigger star, which could explain in part while we'll likely be hearing more about her. But I figure she deserves more or less what she has coming her way.
Fashion: Don’t you recognize me? Death: You should know that I don’t see very well and I can’t wear glasses. Fashion: I’m Fashion, your sister. Death: My sister? Fashion: Yes. You and I together keep undoing and changing things down here on earth although you go about it in one way and I another. Giacomo Leopardi, “Dialogue Between Fashion and Death.”abridged