1200 cals is the floor for women because it's nearly impossible to get all of the nutrients you need in fewer calories by happenstance. it's possible to plan it out and make weird food combinations to do it, but that's something you should really be working with a dietitian on to make sure you are not missing something important.
then you move on to calories. two of the biggest factors in how many calories you burn are your height and your age. at 5'6" i am about average height. which means that roughly half of women are shorter than me. and those who are on the short side have smaller bmrs. then you factor in age. without any amendments, your bmr is going down by about 10 cals a day every year you age after about 24 or 25. so by your midthirties, you've gone down 100 cals a day from your peak and by your midforties you're looking at 200 cals below your peak. so if your bmr in your midtwenties was only 1250, by the time you hit your forties you're looking at only 1050 being your base bmr. so that window of space where you can eat and lose is quite small. because there are a lot of small women on this site. there are a lot of women over thirty on this site.
and then you get to the people with unrealistic goals. yes, the program will let you try and lose 2lbs per week if you are 130lbs, even though you would have to be a about 3'5" for that to be a realistic goal. that's when it just dumps you into the lowest ranges.
couple that with the fact that most people asking questions are relatively new and haven't figured out that you can only lose about 1% of your bodyweight be week [at least regularly] in a sustainable manner or that you have to keep your calories burned number accurate to what you do and that does bump up the numbers in that lowest range.
for a woman who is 5' tall and 50 years old with a slightly slower than average metabolism she might need to put in some hours at the gym to be able to lose on 1200 cals.
for a woman who is 6' tall and wants to lose 20lbs, 1200 is probably too few and way too few if she were working out a lot.
so it all really depends on what stats you are talking about to begin with. if i had to venture a guess, i would say that there are more women than men on this site,there are more women under 5'6" than over on this site, and there are more women over thirty than under on this site. and those factors do increase how close you need to eat to 1200. and if crash and fad dieting do help bring down your metabolism, you're talking about skewing that bmr number down a little more.
so while it does seem like a lot of women are in that range sometimes, there is somewhat of a basis. i mean, if you are in a grocery store in southern california on a tuesday in april, what are the odds of seeing someone wearing a chicago bears jersey? but if you go to the grocery store nearest soldier field the day of a playoff game how many bears jerseys do you think you would see?
-google first. ask questions later.