Thing is, it's not trans people who created the binary gender system any more than it is people born with the organs or hormones or other identifiers that mean all feminists recognise them as women created it. I can't see how either actually benefit from that system either. But, and it's a big but, to some degree, we all have to negotiate the system that assigns relative and status based on gender identity.
I don't believe it is right that society limits human beings to being feminine or masculine because these are subjective concepts, social constructs and often used to contain, control, direct and exclude. I also don't believe it is right that society limits human beings to being male or female because these aren't 100% absolutely determinable every human, and I also believe these categorisations have been and continue to be used as the rationale for containing, controlling, directing and excluding people (e.g. physical, hormonal, psychological explanations for "treating" women and men differently.)
So, unless we want to risk ridicule, isolation, exclusion and even violence (for threatening the "natural order" of things or some such!), we have to be male or female. That's an easier choice to make for some of us than for others. For those who know the label they were assigned at birth isn't right for them, even if they believe they are something other than the other label, they effectively have to opt for the other label.
There are activists in every social and political movement who aren't necessarily representative of all the people they appear to speak for. So often their existence and "way out" views are used as an excuse to conveniently dismiss the movements they are involved in. Sometimes people in those movements feel embarrassed by them. Sometimes though the Arthur Scargills and the Al Sharptons stick their necks out and say unpalatable, provocative things that at least stir thinking. But yes, some activists can appear to be self-motivated and not really care about the impact of their words and actions on others in the movement.
I can only feel despair though when I see some feminists appropriating the methodology of MRAs to demean, to dehumanise, to demonise trans people. I still can't help but think that this is a waste of our valuable time, resource, energy and creativity, leaving those who genuinely benefit from patriarchy, who represent the greatest threat to women (and to trans people as well, as an adjunct of misogyny,) continue to flourish.