Actually, the King and Queen did not throw it in her face. Merry-weather did. The Queen actually asked if she was offended and refereed to her as excellency.

Cursing Aurora was a slight against the three good fairies, are the main characters of this film. If you don't believe me look how they they are focused on getting in the way of the baby when she says she'll curse her, as opposed to her own parents reactions.

She also has a history of doing things to torment them, ruining their best flowers, Anything you can create , I can destroy.

Her not being invited to the party was for good reason, she is a maxim of evil itself and she declares it with vigor several times without being boastful, why would you want that around your baby at a time of blessing? She probably would've given Aurora something that would make her provocative or attract the wrong sorts of things or suitors to her. Twist what the fairies did by giving her beauty.

It isn't until the Queen respectfully asks her pardon on the whole affair that she, turns, looks at the FAIRIES, and says she's going to curse Aurora, because she knows it'll hurt them to do something to two people they care about and their baby, like any godmotherly figures. This story of Sleeping Beauty is just a look into an ongoing war between these Fariy's and the humans in the middle.