I think some are just being realistic about the strengths of male vs female humans, and others are made up BS. And most people lack the ability to process that nuance.
I have a personal example that imo is a realistic portrayal of acceptable gender roles.
Both of my parents worked. At my house there was a lot of grueling outside work year round: the vegetable garden that kept us fed plus the trees Dad cut down and chopped. Maintenance of the land is more physically taxing than many modern people can comprehend. All of the family helped in picking vegetables from the garden, cleaning them and readying them to store over winter. I look back quite fondly of all of us shucking corn, stringing beans, shelling peas, etc.
Dad took care of the outside and the vehicles. Mom took care of the house and us kids. When you see your Dad come in at lunchtime from working hard in the heat for 5 hours straight, it really seems right that there is a meal ready for him to eat and a cold drink.
The problem I see is that a lot of modern men are fine with the gender roles of the woman staying in the house, but the men don't have outside responsibilities. They aren't chopping wood, planting the garden, etc. They are quite literally doing nothing substantive. Playing video games and consuming pornography for multiple hours a day contributes nothing to the household.
Part of it being equitable is that everyone has their role, both are working hard and both benefit from the other person's contributions to the household. Gender roles fall by the wayside when you both work and live in a city apartment.
I think some are just being realistic about the strengths of male vs female humans, and others are made up BS. And most people lack the ability to process that nuance.