I still get the impression of blond hair as represented in anime (and possibly anything made in Asia and Africa assuming if anime is made for a Japanese audience though Africans and other Asians share similar stereotypes) as so othered that whilst not necessarily always good or bad, it’s so different as to be almost alien if it weren’t for that many Asians and Africans were never blond in their childhoods.
So far the biggest point of reference for blond hair in general’s almost always due to foreigners, fashionable characters, delinquents and albinism that whilst not always the case, I do get the impression of blond characters (whether if this includes both light brown/dark blond and white hair) as practically much likelier to be othered than in Western media. Again not always the case.
But given the media (anime included) can shape people’s perceptions and biases, whilst some can give a fetish (foot fetish, blond fetish, whatever), sometimes it can give some people bad impressions of others. That’s not the right word for it but it doesn’t help that some anime depict blondes as fiery-tempered, shady or delinquent that it makes some people think those women are unapproachable.
Or in the case with blonde tsundere characters, hard to please and impress at first.
(This also goes for people who do encounter delinquents, fashionable people, Westerners and even those with albinism in the flesh.) Not always the case but I suspect if it weren’t for foreigners, the other three biggest reference for blond haired anime characters are fashionable people (though this also overlaps with Westerners in the sense of stereotyping Western people as rich and fashionable), delinquents and albinism.
Some schools don’t alloy kids to dye/bleach their hair but some with naturally lighter hair are suspected of such that a pupil got mad at a school for thinking she bleached her hair. This would be just as bad for those with albinism, where such an odd look would easily make them targets of gossip, mockery and the like. If it sounds odd, keep in mind most Japanese (actually most Asian and African) people were never blond in their youths.
Most of them don’t have blond hair either (whether if both white and light brown hair also counts as blond) so it seems if it weren’t for foreigners, the biggest points of reference for blond hair are fashionable people, people who simply have naturally lighter hair (albinos included), delinquents and possibly those who bleached their hair by accident.
There’s another Japanese source where I recall why some people dye their hair lighter’s to look different. So for whatever reason and circumstance, blond/light hair isn’t necessarily unattractive but so different as to attract both good and bad attention.
(Keep in mind there are people who do bleach their hair as part of their corporate image and some bleach it to ward off unwanted male attention.)