For instance, any legitimate discussion or criticism about gender-affirming care, possible social cause that's driving the increase of trans-identifying teenagers (confounded by high rates of autism, mental illness, trauma), or how certain trans rights infringes on women's rights, are framed as "transphobic" by these medical and activist organisation. This would also mean that statements made by countries that are arguably more progressive than the US (i.e. UK and European countries) about the current trans issue would fall into that category as well.
Now, against the backdrop of the capture of cultural institutions by radical activists in the US who share a common foundation (critical social justice), it's hard to be sympathetic towards your claim that prejudice is what's holding them back, when the actions of the medical and activist organisations in the US is consistent with the silencing of valid criticism that other factions of the critical social justice adherents (i.e. race) have a track record of.
In other words, it's hard to believe that the medical and activist organisations in the US are actually acting in good faith; they are weaponising our empathy for marginalised groups to silence legitimate criticisms about a medical scandal and the ideological foundations driving the scandal.
Edit: Anyone of sound mind can clearly evaluate that my point isn't transphobic. The reply to this comment is a demonstration of what's wrong with the US.