Because you're using the labels "men and women". Take a closer look, you'll notice that the men that are interested in trades, overlap with one segment of the Lesbian and Transmen segment of people. For all that matters, the reason those jobs appeal to those people are because they are not hiding their interests. For a lot of other women who would like to be in trades but aren't, they don't want to either out themselves, or appear to be gay if they aren't. The negative perception is that women just can't do the work.
The same holds true on the other side. Women interested in nursing, and childcare, overlap with one segment of the Gay and Transwomen segment. However this is where things get ugly. There is an entire negative perception that Transwomen and Gay men abuse children. So that's why childcare is often not a thing men want to get into. Nursing, not so much, it's typically the lack of aptitude for responsibility that gets men removed from Nursing programs.
There is pressure, on everyone, to conform to their gender label. I'm sure there are plenty of people who are unhappy in their job, are only unhappy because they don't want to be there, and are only there because of not wanting to appear as less of a man/woman.
It is not a biological reason why these interests are the way they are, it's entirely a social-cultural thing. If you were to remove all outside influences, and give kids their choice of toys without labeling them as "for boys" or "for girls" , you'll find there's no significant difference that way.
https://www.theguardian.com/lifeands...ender-research