Both and neither? The language itself isn’t the core issue, it’s the overt repudiation of someone’s identity. The biology bit is just an excuse, made worse by it being wrong: https://blogs.scientificamerican.com/voices/stop-using-phony...
If gender is a social construct then it doesn't really exist except as a cultural artifact. If your identity is based on any kind of social construct, I don't see how it follows that anyone has to agree with or affirm that such claims ought to be a cultural norm.
Furthermore, disagreeing with such claims are cultural disagreements rather than moral disagreements. Cultural disagreements are not innately hateful. Therefore it doesn't seem to follow that affirming gender identity has any moral force, or that not affirming it is innately hateful.
That said, this obviously doesn't justify harassing trans people in any way, shape or form because of such disagreements.
Using another analogy, I have vegetarian friends and acquaintances, and when they come visit, I serve us all veg-friendly food because... I'm not an asshole! Doing this small act does not require me to adopt their religion or become vegetarian myself.
It's not just about respect anymore; it's about truth.
https://www.newyorker.com/sports/sporting-scene/how-one-swim...
Because we didn't want to her feelings Mia, a biological male with a female gender was allowed to compete in women sports. She's dominating that sport now; and it's starting to display a comical mismatch between the old reality and a new reality.
The argument is more complex then simply truth and etiquette. Because proponents of etiquette are literally redefining objective truth. So when you talk to both sides, they literally think they're side is the objective truth. Truth is as fluid as gender and it's literally hard to know which one is real.
There is as much validity to say most humans are male or female as there is to say that gender is a gradient, a small minority of people are neither male or female. These are just arbitrary categorizations that are being redefined.
In order to have my respect and niceness, you have to ask for it with respect and niceness. Otherwise you're just begging for abuse, and you have nobody to blame but yourself when it comes. I suspect I'm far from the only one who see it this way.