posting alarmist, exaggerated stuff about binding rendering kids unable to even walk and enjoy the fresh air doesn't help the cause.
But you don’t disagree that young females wearing binders are, in fact, self-limiting their sports participation because of the extra needs due to wearing binders. So, in fact, they are causing some degree of harm and, in extreme heat, even their support charities say to not walk around in the heat.
I, personally, think that this is alarming behaviour. I know schools are not able to ban binders, however, this is surely where a newsletter such as this, needs to point out the realities of wearing a binder. Not just add links and expect the best outcome. And a teacher needed to approve this, so where was the safeguarding here.
So, a school allowing this newsletter to be sent is, by my reckoning, worth sounding the alarm about.