99% of women do not have the BRCA1 mutation.
The BRCA1 mutation is a very bad thing, it represents a gigantic increase in the chances of getting breast or ovarian cancer.
In women, the chances of getting cancer are 1 in 58 for ovarian and 1 in 7 for breast cancer, so a mutation correlated to 10X the risk of ovarian cancer and 5X the risk of breast cancer is substantial. Women who have the BRCA1 mutation are making a reasoned decision - argue about whether it is the right one or not as you will - but women without it are not being reasonable at all if they do what she did.
Often lost in media stories are the risks of preventive interventions. For women with the BRCA1 mutation the risks of preventive intervention make some sense but for women without it the risks of preventive intervention remain the same while the risks of getting thing being prevented are far less.
Dr. H. Gilbert Welch, professor of medicine at the Dartmouth Institute for Health Policy and Clinical Practice and a co-author of "Overdiagnosed: Making People Sick in the Pursuit of Health", defuses a lot of worry in his CNN piece: What Angelina Jolie forgot to mention
Should you get tested, since 99% of women don't have it? Sure, but only if you have a family history of cancer. Angelina Jolie's mother died of ovarian cancer at age 56 so getting tested made perfect sense.