There are millions of such people, but it's not based on sex.
People from the bottom parts of intelligence distribution are a "burden", because no amount of labor they produce will generate more value for society than they consume (in food, housing, healthcare).
In developed countries we are able to collectively shoulder such a burden, because we do not live an a resource-scarce environment like you mentioned (when it comes to basic necessities)
> The idea that someone is a permanent burden regardless of what they do is hard for me to wrap my head around.
Don't get fixated on the "permanent" part of this. Some people can generate positive and negative value through different periods of their lives. Kids < 16 years of age are typically consumers of value. So are seniors of 80+ years.
This is not a bad thing, just a natural cycle of life.