I'm a lifelong sufferer of ED (in control now) and I've made this connection too, in many different ways:

1 - The social contagion aspect of it

2 - That it's the mind's way of distracting the person from some other trauma. (When you delude yourself into thinking "When I'm 80lbs / a boy, everything will be perfect and my life can finally begin" you are completely avoiding all your actual problems and blaming all your hardships on your weight/sex and you're in for a big shock when you finally achieve your goal and you're still as miserable as ever.)

3 - Unrealistic goals. Back when I was active in pro-ana communities, people would post thinspo of supermodels, very tall women, and most likely photoshopped (though we didn't really understand the magic of photoshop yet back then.) In the same way, I see many of these trans people posting goals of anime girls. Like................... At least the supermodels were human. And thinspo like Mary-Kate Olsen was very attainable because she was 5'2. It feels like the trans not only have no idea of what's attainable and what isn't, they get angry when people around them don't validate their fantasies about what they look like. How dare this lesbian not see that I am a hot woman, uwu???

At least for teenage girls, ROGD really does feel like Anorexia 2.0