While it seems disrespectful to the LGBT crowd for Pitt and Jolie to go back on their word, the thing to remember is that they're human, fallible like everyone else, and they'll have to deal with the fallout of their pronouncment, if there is any.
The other thing to think about is that Jolie recently had a double mastectomy, and perhaps feels that pull of death that claimed her mother at a relatively early age. I'm only speculating here, but maybe she wants that kind of 'permanence' ostensibly offered by a marriage vow to kick back at the disease that took some of her flesh away.
As for those sniping at her looks, beauty is in the eyes of the beholder, yes? I never thought she was that attractive, but certainly not ugly. And she's worked hard to become IMO a first-rate actress. So them's my thoughts.