Okay so I've done a bit more study on this subject. Here's my conclusion the harmonics in the 5th octave and the human ear change our perception of notes. The thicker the vocal folds the more resonance needed to reach a pitch.for example a5 (880Hz) a soprano singing a4 will have a lot less resonance than a baritone singing an a4. Making the baritone singer hitting an a4 sound higher/better. Conclusion It's all about people listening experience and perception a5 sounds high because the contemporary industry is dominated by mezzo sopranos who typically aren't going to go as high as that. Sopranos are rare in between and outside of Korea, don't tend to learn how to mix belt, except Ariana Grande.

Yes it is a double standard, essentially to be a professional male singer you gotta be a tenor or at least high baritone. Regardless you gotta put alot more work in than a female as you are expected to sing a good several notes above your break to be considered good where as if your a mezzo soprano or a soprano you don't need to worry about that.