If we want to trace back the etymology of the term "guy" we would unearth some interesting facts. The most infamous "Guy" of the 17th century is Guy Fawkes, would-be Catholic terrorist.

https://en.wikipedia.org/wiki/Guy_Fawkes

Guy Fawkes is most notorious in the UK today as the progenitor of Guy Fawkes Night, where children solicit "a penny for the Guy?" and the funds raised ostensibly go to construct and burn a large straw effigy of Guy, in order to celebrate his defeat and the survival of the Parliament. He was executed, not by burning but by hanging, but nevertheless Guy Fawkes is the original Burning Man.

Guy Fawkes Night was imported to the United States during our independence, and it became Pope Night, a night of mayhem and anti-Catholic vandalism and hooliganism. George Washington once told his military troops to knock it off with the Pope Night shenanigans, because it was alienating Canadians.

So the term "guy" became genericized, beginning in Australia it seems, to refer to a grubby lower-class Catholic boy. After a few centuries of circulating in this way, it lost most of its derogatory connotation and became a generic way to refer to men or boys, and by extension, girls and women.

I don't take offense at being called "guy", nor would I if I were female, and especially because today in the USA, it is so generic and inoffensive. Nobody recalls its sordid roots, even if Pope Night is making a resurgence around here.