Because that's how they've been socialized to be and men have been socialized out of that. Culture matters way more than gender.
The Aka, foragers who live in Central Africa, are some of the most hands-on dads in the world. “Fathers are within arm’s reach of their one-to four-month-old babies more than 50 percent of any 24-hour period and are nuzzling, kissing, hugging, or mostly just holding them a whopping 22 percent of the time they spend in camp. Even when Aka parents go on hunting expeditions in the woods, they take quite young infants and their other children along, being careful to remain in constant contact.”
“Almost invariably, fathers in hunter-gatherer societies spend more time with infants than fathers in most Western societies do, and much more time than fathers in farming societies. Indeed, in many farming societies fathers never hold their infants at all.” Hrdy, Sarah Blaffer. Mothers and Others (p. 128).
Construction has been hostile to women for hundreds of years. In the Middle Ages, women doing construction were considered just slightly better than prostitutes. Then eventually, they were banned from those jobs altogether. Don't you think that had an impact? In a patriarchal society, where gender binaries are considered important, men don't want women doing "men's jobs" and treat any women daring to attempt that with hostility and often violence. The British NHS just reported that women surgeons get routinely and openly sexually harassed and even groped WHILE on the job. Worldwide, more than 40% of entry-level workers in mining are women. They don't stay on at the same levels as men because of discrimination, lack of opportunity to advance, harassment, etc.
Other than upper body strength, there are no inherent differences between men and women (and some women are much stronger than you are). Please stop with this retrograde nonsense - of which there is zero reputable scientific proof. There are differences between individuals and there's a huge impact of gender binary socialization. Other cultures have different norms (the Mosuo women do all the farming), and at different times in history (in ancient Egypt, women did the mercantile and legal business while men stayed home and did the weaving).
How something looks on the surface is not a "scientific" indication of anything at all and pretending like women really are just different from men only bolsters discrimination and inequality.
