From a Feministing comment:
Yes, she’s blonde, young, wealthy, and thin, but is that really what makes her opinion invalid?
The answer is obviously yes. Being blonde, young, wealthy and thin, (or to simply be attractive to men), reduces a woman to being a helpless tool to the Patriarchy. Worse, a woman intentionally doing anything that might make her more attractive to men, such as getting breast implants, wearing makeup or not eating that seventh bowl of ice cream, is nothing less than sex treachery.