What I think you’re missing here, as other posters have noted, is the fact that aesthetic standards of acceptable appearance for women have a built-in skew toward pleasing the male gaze. Even when men aren’t the ones directly promoting or enforcing such standards, they’re the ones for whose benefit the standards exist in the first place.
Even when men are covertly bragging about how oblivious they personally are to the aesthetic details of female appearance standards (and by extension, bragging about how they’re too manly to even notice any of that frivolous girly stuff), the fundamental reason that those standards exist is still that women have traditionally been expected to strongly prioritize being visually pleasing to men.
This is an example, IMHO, of the classic Societal Oppression Catch-22, in which oppression is entrenched by setting up societal structures that pressure members of the oppressed group to behave in a certain way, and then mocking them for complying with the behavioral expectations. Usually the mocking is done by the very people for whose benefit the oppression was instituted in the first place, and who in the meantime have come to view this behavior as just a “natural” defect in the oppressed group. For example:
Patriarchal society: “Women are not intended to have lucrative careers or professional achievements or influential status. Those roles belong to men, who confer their benefits on the women they marry.”
Women: (channel their personal ambitions for wealth and status into obtaining wealthy high-status husbands)
Men: “OMG women are so shallow and heartless! They run after wealthy marital prospects and ignore decent guys who aren’t rich!”
Similarly:
Slaveholding society: “Slaves are not entitled to autonomy or rights, and any indications on their part of serious thought, attempts at self-education, dissatisfaction with their lot, etc., should be harshly discouraged because they may well lead to rebellion and violence.”
Enslaved people: (cultivate submissive cheerful unintelligent demeanour to avoid punishment for “uppityness”)
Enslavers: “Sheesh, these slaves are just like children, so naturally happy and foolish! How unfit they would be to look after themselves!”
And countless other examples. In this particular case, we have
Patriarchal society: “It’s very important for women to be physically attractive and visually pleasing to men, and their degree of social approval largely depends on this attractiveness.”
Women: (develop and uphold conventional standards of clothing styles, cosmetic use, etc., to accentuate their physical attractiveness)
Men: “Wow, women are so frivolous and fussy about their obsession with ‘fashion’, I hardly ever even notice what a woman’s wearing but they seem to consider it such a big deal!”