Does anyone ever think that young people are brainwashed into this gender issue.
I'd say less brainwashed and more they've been given this framework as part of wider conversations of adulthood and they're running with it.
I've had some teens and tweens disclose to me that they thought they might be trans. Thankfully, none of them had any distress with their bodies, just some normal annoyances. Talking with them, I think they're just taking what pieces they have to figure things out when they don't have anything else.
A couple of examples: one was an older teen boy who had spent years having people tease him for being feminine, called him a girl, and so on. He disclosed he had an interest in things like skirts and spent lockdown regrowing out his hair and having mixed feelings about his bullies being 'right' and that he might be trans. He mainly needed no judgement, no expectations space to talk it all out.
Another was a 12 year old girl who, like many, was dealing with a lot of issues around what's expected of girls. She said she was 'thinking of going non-binary' entirely because she hated those expectations and hearing how she wasn't really a girl because she wasn't good at this or that as a girl she should like that. She knew she would always be female, she just hated those comparisons and thought going non-binary was the solution as she's been taught the definition of 'being neither girl or boy'. Again, space to talk about it, how that I could see why she would think that but it had its limits, and we worked out ways she could try things like doing sports outside of school where she doesn't have to be compared and using D&D characters to try out neutral names so she doesn't need to 'out' herself at school. I did correct a friend who joined a later conversation to ask if she's picked a 'non-binary name yet' that any new name would be hers, not a gender's name.
We have kids in a stressful society, being pushed to think about their futures all the time (I fucking hate that at 11-12, kids are being talked what looks good on their CVs). They given gender identity information in a not very different way to sexuality and 'aspirational' career information as part of considering the future rather than like religion/ethnicity/cultural concepts that might suit it better. There is very little space for many kids to actually digest and consider those frameworks beyond the definitions they've been taught and see around them. Like I said, I don't view it as brainwashing, I view it as a limited framework that schools and others feel they should be teaching somewhere and have largely fit it in to relationship and sex education. Kids are working with what they've got while like every generation trying to work out their emotions and place in society. Discussing how limited any framework is needs become part of it, I think.