Flutes are not girly. In the first book of paradise lost, the hosts of hell march at the sound of "flutes and soft recorders". Of it's good enough for Satan's army, I say it's good enough for a highschooler.
There could have been a dozen other examples. Perhaps dancing, or cheerleading, or computer nerding, or whatever else. All of which have had various social stigmas in various groups at various times.
But perceptions are certainly different.
Several studies [0][1][2] have found significant differences in gendered participation in various instruments, and the perception by others of people playing instruments typically played by other genders.
Further, at least one study [4], has found that this variance vanishes or flips in queer ensembles.
Anyway, I wanted to check because Paradise Lost was a long time ago. Men were the first to wear high heels, after all. I figured there'd likely be a drift from times where flutists were male because ensemblists were male to now where anyone can be seen as gay for just about any reason.
[0] https://www.researchgate.net/publication/264200609_Musicians...
[1] https://digitalcommons.lib.uconn.edu/vrme/vol5/iss1/3/
[2] https://theath.ca/arts-culture/instrument-gender-bias/ (mentions a different study)
Traditionally, Manly Men are not supposed to put phallus-stuff into their mouths.