This would be plausible if I had ever heard a straight man talk about the guys he had dated.
But I've definitely heard people refer to groups composed entirely of women as "you guys".
And anyway the masculine plural being genderless is a convention of romance languages, which english is not. It is not useful or consistent to describe expectations for english usage in terms of the features of other languages. Negative concord and invariant be are common language features globally but you don't hear white americans scrambling to include them in standard usage.
Identity politics has resulted in certain groups making concerted efforts to try to eliminate such usages, but it's still an ingrained part of our language.
If you call a plumber and they say “I’ll send a guy over”, there’s no implication that it’s male. Singular and genderless.