It is important isn't it?
I think it's absolutely the crux and has been for a while.
My personal experiences of teaching a gender questioning pupil with asd was entirely based in media.
His personal interests were all from certain tween shows on satellite tv. He was just into the "wrong" clothes and toys. He had no expressions of being in the wrong body till that concept was introduced to him by an older child/ teen who had watched a documentary.
The films on YouTube for years have been of so many who essentially advertise and glamourise and then project their own experiences. Also tumblr, chat rooms etc.
There was a particular algorithm on youtube for a period of time that brought up similar videos to what you'd watched. It's been changed now (only a little!) as it was implicated in the increase of flat earthers and fake news.
It's the same processes described by Oliver James in 'the Affluenza Virus' whereby media, tv and advertising has been directly linked to rises in depression, anxiety and anorexia around the world. We can be very influenced by visual images.
We all know how ana sites and self harm images on Instagram have influenced vulnerable children and young people, especially girls.
For me though, the way women and girls are presented in all visual media now and in the past has a big part to play. Both through objectification and how girls react to that objectification. And porn too.
Girls don't have to actively seek this stuff out to be affected by it. It's everywhere.
And being trans and getting mastectomies has definitely been glamourised.