I read her article - thanks, OP. As usual when reading these earnest self-justifications, I ended up thinking "this is crazy". They're rebelling against something they could just ignore.
Enid Blyton's character George doesn't have to be trans, nonbinary or what Sasha calls a boygirl. She's just herself: a female child preferring those activities which, in the 1940s, were stereotypically ascribed to male children. She just got on with it. She had friends, school, a nice family - she wasn't hated, excluded or any of the other awful abuses trans activists claim will happen to kids who don't conform to gender stereotypes.
We all knew some kids who didn't; many of us were those kids. The Famous Five books were written over EIGHTY years ago! There've now been four whole generations of women and men bucking 'gender' and just fucking getting on with their lives. The stereotypes themselves have weakened significantly: in Blyton's time and my own, girls and women were constrained by law.
Young people like Sasha have none of that to contend with yet, mystifyingly, go out of their way to re-solidify gender constraints while protesting their need to escape them.
Pfft!