Human society has always been glorifying certain body types and physical violence all the way back to ancient Greek and very likely way earlier. There is nothing wrong with admiring and chasing after a fitness ideal.
To make a steelman out of this case, I guess we can argue overexposure and extreme promotions of unrealistic ideals can warp impressionable young minds. But even then I disagree that Youtube alone has the moral standard and authority to regulate and censor this. They are a corporation, one of the least moral entities currently around in modern time. They have no right to pick and choose what kids can and cannot watch.
Does this change your view of Youtube's new stance?
> YouTube said it will now limit repeated recommendations of videos that: Idealise particular fitness levels or weight groups; Compare and idealise certain physical features, or; Are socially aggressive, meaning they show intimidation or fighting.
> YouTube already restricts teenagers’ access to some content involving eating disorders and physical fights.
So they've expanded the ana/mia content recommendation filter to encompass fitspo and maybe are expanding the fighting filter in some way. I can't tell if that middle line item is thirst traps or incel face shape analysis.
Nothing seems especially egregious here. I don't think this will impact relatively normal health and athleticism focused channels.