Age 14 doesn't strike me as a particularly young or naive age to me. I was surprised that you were surprised.
When I was 6, a 14 year old boy in my neighborhood tried to grab me and kiss me when I was using my next door neighbor’s trampoline. When I was 9 another 9 year old boy I didn't even know at summer camp pinched my butt. I told the camp counselor and she said it didn’t mean anything. Boys at school when I was 10 or 11 talked about "sluts" and called each other "f@gs". Also when I was 11 two boys in 7th and 8th grades (they were probably 13/14) trapped me in my seat on the school bus and violently tried to grope me on several occasions.
When I was in art class age 12 and there were only boys in the class but for me, Little Red Corvette came on the radio and the boys said, "Yeah, more like Little Red P^ssy" and laughed, then suddenly realized I was there and apologized. When I was 13 a strange boy with no social skills stalked me at school and apparently his conversations behind my back were so obscene and aggressive that other boys broke the "bro-code" and came to warn me about what he was saying. Etc. etc. ad infinitum.
I never assume that being "Liberal" includes being educated about sexism or being less sexist than anyone else. These days the line is that Western Women already have it so good that any complaints they have about sexism are trivial and "karen"-like. Like we've achieved equality so why don't we just shut the f^ck up? Compared with women in Saudi Arabia and parts of Africa we have nothing to complain about.
And people also seem to believe in automatic progress, as if the mere passage of time means things are getting better. I don't see an improvement now in how boys talk about girls over when I was a child in the 1980s. In fact, I think the vitriol and resentment of attractive young woman has skyrocketed. The rate of girls being sexually harassed in middle schools and high school is way up, as are rates of preteen and teen girls' depression and suicide attempts. Access to the most extreme forms of porn can be assumed for the average 10 year old today. Memes about "sluts" and "gold-diggers" spread a million times faster than before the internet and social media.
The ancient resentment of boys and men toward girls and women they find attractive but who they "can't have" (or just believe they can't) comes back over and over, and is projected as hatred onto girls and women in general in a way that would be unthinkable for girls who were rejected by boys. This must be multiplied by the young male sex drive as well as a sense of entitlement that girls don't tend to have. A girl who likes a boy who is not interested in her turns that hurt and anger on herself, not on the object of her love. The boys take their rage and hurt at being rejected and turn it into a group anger, a shared bond with other males in their hatred of women.
If anything, because there was a feminist movement in the 1970s some parents (usually but not always Moms) woke up to how things were and started talking to their kids about equality of the sexes. This was part of the zeitgeist back then and it carried somewhat into the 1980s. But then it gradually dissipated.
Later the "sex positive" third wave feminist movement started, and unfortunately many men took this as a chance to revive the old Madonna/Whore paradigm where some girls are nice enough to bring home and marry and the rest are "sluts." Now they often say that no women are "pure" anymore so it's more like a Whore complex (Madonnas being rare mythical girls that are virginal and loyal and you can find them of somewhere in a foreign country or a Fundamentalist Christian household.)
It’s hard to be an aunt or other relative in that situation when you don’t know how the parents are handling things and you know they don’t want you usurping their role. In my experience, messages about respecting women are more easily received when boys hear them from men.