No. Something being subjective does not render it meaningless. There are many things in this world that are subjective and also meaningful.
Examples, kindness is a something that is very subjective from culture to culture. Hell it’s even subjective from person to person. What I think is kind for me on one day is very different for another person on another day.
Another example, the pursuit of happiness. What makes one person happy is often radically different than another person, because people are different.
Honestly is subjective. I remember my grandmother who was the most honest person I know, tell the strange man who was following us her husband was waiting to take us home. She was divorced and lived alone, and my parents explained she wasn’t a liar, she was just concerned we were about to be assaulted.
Subjectiveness does not make something meaningless, it does however make things more complex. Gender is a little more complex than these charts abs histograms around sights, stereotypes, and sex. I’m sorry if you have trouble understanding the complexities of these things, but just because something isn’t black and white doesn’t make it meaningless. Complex emotions, identities, and feelings are part of the human condition.