BMI is overly simplified though. Height and weight are a good starting point for determining health but some women aren't exactly unhealthy just because they have big tits and thick thighs bringing their weight up.
From an epidemiology standpoint in medicine, BMI is pretty useful. You have to be pretty fucking jacked for it to not be valid and any clinician worth their salt will know a super muscular dude with great blood work is not going to be at higher risk of certain illnesses because of BMI.
But like the overwhelming majority are due to people obviously overweight in terms of body fat, they carry their weight viscerally, and their bloodwork shows it.
As for women, they don't have a male body habitus. Meaning they won't carry weight around their belly, at least initially. For many women, thighs are the first place it starts depositing. Women with really thick thighs are on their way to developing more of a traditional obese body habitus.
i'll never understand why people keep defaulting to the extreme exceptions when trying to invalidate BMI. It's like, we get it, anybody worth their salt already knows the limitations, but those limitations are overstated in virtually every instance.
Women inherently carry more bodyfat than men, it's not just the differences in where they store it.
Women with curves (actual curves) are not overweight. It doesn't take a super jacked guy to dupe the system.
You can take one look at multiple women of equal height and weight and see which ones are actually meant to carry that weight.