Most of the fitness content I see is focused on correct form and training technique and not on physique.
Likely this is a preemptive move to try to avoid regulators banning those lucrative areas by virtue signaling and restrict the channels that doesn't make them lots of money.
They're not banning anything, they're just not encouraging people to continuously watch that type of content. But also they did mention that.
Also pretty much anyone can call themselves a personal trainer, so you have people doing 6 week courses and then considering themselves professional coaches.
I keep trying to convince a friend whose a "proper" (top powerlifter, played rugby, can olympic lift, masters degree) personal trainer to make "garbage" content. e.g. instead of having an upper/lower split or something else sensible, make it a left/right split. So every day you do full body, but only the left or right side of the body.
Call it a revolutionary training method that fixes muscle imbalances since you only do unilateral exercises. I bet that idea could trend despite it being mostly garbage advice with a few facts mixed in.
Given a monetary incentive, people will turn themselves into bs promotors.
E.g. the attitude at 41:46 https://youtu.be/eKBDacpRYSU?t=2506 seems like a good one to promote.
That fellow's opinion in that short segment seems fine enough, but he's just saying that it's good to work out and get stronger, and that it'll probably help you stave off depression (also somewhat dubious in the context of this subthread, even though I'd agree). He's not saying why I should have six pack abs, or 3d shoulders, which are all vanity driven and potentially obsession creating. It's a pretty subtle difference.
I don't agree that lifting for appearance is something to promote to teens, because it just starts from a place of banking off perceived anxiety about one's image, and I tend to find that people who are mostly concerned about their image, tend to kind of suck. That's just different than talking about how working out will help you feel better by being stronger, being more capable, and yes potentially more attractive.
It's like gambling advertising imo.