Why is it not appropriate? Because she's a woman and should only be confined to wearing a dress? If men can wear suits, why not women?
I will add this: Consider it from a female viewpoint, women were being told exactly what to wear for centuries. It's only in these past few decades, trailblazers like YSL, Marlene Dietrich and Katharine Hepburn have empowered women by breaking boundaries with womenswear. A woman wearing a suit actually represents something. Jolie is in a formal evening suit, I fail to see how she is underdressed.
We've seen enough pant suits worn by women on the carpet over the years where it's no longer shocking or even interesting.
Lupita in that Dior dress!
Uma looks great even if the dress is a bit boring.
I don't think there is much chance of anyone mistaking Angelina Jolie for the catering staff.Well, I hope Angie doesn't get mistaken for the valet or catering staff at the after-party because, honestly, that's what she looks like.
Once again, Lupita sets the standards for true glamour on the carpet. I think she is working her way through the rainbow.