On a fundamental level it's weird to me that we have these strict binaries - male or female. I've often wondered, and will probably get laughed at for this, why when we're born we can't be non-binary (sorry to use this label again but for lack of a better word) and then decide to be who we want to be without fear of judgement. Maybe I'm being a bit silly. Don't get me wrong I have a child and she is the sex that she is biologically. But if she came to me when old enough to make an informed decision and told me she was something else I'd fully support her.
I’m not really sure what you mean by “us” having these strict binaries. Nature decided for us. We don’t start randomly deciding what sex babies are when they are born and imposing hard lines that weren’t already there. We just observe sex and record it. Humans may have overlaid gender on biological sex, but biological sex is identifiable and it is relevant.
We don’t need to insist everyone is “non-binary” when they’re born and we don’t need to tie ourselves up in knots recognising anyone’s “non-binary” identity as an adult, we simply can accept that kids will be kids and find themselves as they grow up, and adult male or female people can dress, act, present, love, live however they want. There is no need to create endless categories of recognition for gender because it doesn’t really matter any more than what type of music any of us likes. You do you. But sometimes biological sex is very important and that must be noted. We all know where babies come from, for example, and Mother Nature doesn’t care about your gender identity for those purposes. Prostate cancer doesn’t care either. And so on.
That’s not the same as saying biological sex determines every single thing we do — in fact those who challenge gender firmly challenge that. It’s IMO a toxic idea that there are behaviours or mindsets that mean a person isn’t “really” the sex that they actually are. I suggest society needs to reframe its thinking on this, we have gone down the wrong track.