Transmeds are not TERFs
What are transmeds?
Transmeds believe transsexualism is a medical condition. They suffer from gender/sex dysphoria, which in their opinion requires medical interventions. They are against "the trans ideology" because they, quite correctly, understand it eventually will only lead to general hate towards them and elimination of existing trans medical care.
What are TERFs?
TERFs believe sex is immutable. Even though the more moderate wing of TERFs acknowledges that transmeds are not "predatory men" and may even sympathize with them, they see transmeds as victims of "the trans ideology" rather than their "true gender".
Some transmeds (especially ftms) may eventually detransition. They were true believers of "brain sex" and once disillusioned, many of them naturally convert to TERFism.
Why do some people here say "transmeds are TERFs"?
They say it because they hate both communities. They hate transmeds because their "transness" is all about identity/validation and any criteria held true by transmeds invalidate them. They hate TERFs because TERFs (including the moderate ones) see them as predatory men. While it is possible for transmeds and moderate TERFs to have civil discussions and agree to disagree, the gap between transmeds-are-TERFs folks and transmeds/TERFs can never be bridged.