1. Establish that calling something transphobic, terf, etc is inherently illogical and thought-terminating. In addition, detransitioners aren't being heard enough, for what's literally a worse position to be in. Not all people are coming from a pure hate perspective.
2. The T is different from the LGB, and not just from how they are treated. Namely that T is a mental disorder: Gender dysphoria is literally classified as such, and the "opposite sex brain" would definitely be a mental disorder. This isn't a bad thing, in liberal logic - is being autistic somehow a wrong thing? However, the T latches on to gay rights talking points like "conversion therapy!" and act as they fit into society as well as the LGB even if not oppressed.
3. Propose that some trans people have, or COULD have, underlying issues (anecdotally,
as seen here) that manifest as gender dysphoria. You might be able to go into the zinger (autogynephilla) but you can't say it by name. And if you do bring it up, you have to be clear that most trans people are not like that.
4. Big pharma evil and big pharma benefits from trans people, aka new lifetime customers. And as shown by detransitioners, such as the Kiera Bell case, at least some clinics are not doing their due diligence from therapist to psychiatrist.
5. The way trans people are being treated would NEVER be accepted in ANY other medical field. You can't just self diagnose autism or BPD, and anyone who does should be questioned. However, GD is only really detected due to self diagnosis ("I FEEL like a woman"). Outside diagnosis would be incredibly sexist; just because a boy likes dresses, doesn't mean they aren't a boy (and could just be gay).
As a therapist, you wouldn't give an anorexic person liposuction, and DEFINETLY not as their only treatment, while blaming their mental health problems as oppression. Even more damningly: trans-ableism (body integrity identity disorder). They don't feel like an arm fits, so why not chop it off?
Finally; women under duress aren't allowed to get a mastectomy due to castration and "could change your mind" ; while trans people of 18 can get one just fine?
6 Bad faith trans people exist. People like Ashton Challenor, Yaniv, CWC... People who definitely are associated with pedophilla, protection, and AGP; respectively. In addition,
people are willing to shame the LGB for sex/relationships; and even if they are "just on twitter/tumblr", they influence LGBT circles with zero criticism. No matter how much in the minority they are, they latch onto the trans movement in order to gain practical immunity from criticism and spread their toxic messages.
7. TRAs in general are imposing trans identity on kids and teaching them about sex which is like no (Mermaids UK among others).