The Institut für Sexualwissenschaft was run by Magnus Hirschfeld, who had his German citizenship revoked and died in exile. The book burning was a clear signal and erased a huge part of research on queer people, as so well stated in this post. Today's equivalent could be the removal of online resources and the withdrawal of access and licences to ressources once free or purchased.
The Wikipedia article on Magnus Hirschfeld captures extremely well what Magnus Hirschfeld's research meant to individual queer people and to the queer community as a whole. I so wish I could stop being afraid of history repeating itself.
Content Warning: Mention of Suicide
In particular, Hirschfeld cited the story of one of his patients as a reason for his gay rights activism: a young army officer suffering from depression [...], leaving behind a [...] note saying that despite his best efforts, he could not end his desires for other men, and so had ended his life out of his guilt and shame. [...] the officer wrote that he lacked the "strength" to tell his parents the "truth", and spoke of his shame of "that which nearly strangled my heart". The officer could not even bring himself to use the word "homosexuality", which he instead conspicuously referred to as "that" in his note. However, the officer mentioned at the end of his suicide note: "The thought that you [Hirschfeld] could contribute a future when the German fatherland will think of us in more just terms sweetens the hour of my death."
https://en.wikipedia.org/wiki/Magnus_Hirschfeld
Btw, this is how conservatives keep getting to claim that trans people are a new thing no one has ever heard, because our history and existences have continually been erased or obscured systematically through out history.
The most famous example was 92 years when the Nazis raided the library of the Institut für Sexualwissenschaft, the medical practice where the term transsexual was first coined and the first gender affirming surgery was performed in in 1931.
What did the Nazis do after raiding the library on May 6th, 1933? You may be familiar with these images
It is happening again.
Rowling isn't denying holocaust. She just pointed out that burning of transgender health books is a lie as that form of cosmetic surgery didn't exist. But of course you knew that already, didn't you?
I was thinking I'd probably see one of you! You're wrong :) Let's review the history a bit, shall we?
In this case, what we're talking about is the Institut für Sexualwissenschaft, or in English, The Institute of Sexology. This Institute was founded and headed by a gay Jewish sexologist named Magnus Hirschfeld. It was founded in July of 1919 as the first sexology research clinic in the world, and was run as a private, non-profit clinic. Hirschfeld and the researchers who worked there would give out consultations, medical advice, and even treatments for free to their poorer clientele, as well as give thousands of lectures and build a unique library full of books on gender, sexuality, and eroticism. Of course, being a gay man, Hirschfeld focused a lot on the gay community and proving that homosexuality was natural and could not be "cured".
Hirschfeld was unique in his time because he believed that nobody's gender was either one or the other. Rather, he contended that everyone is a mixture of both male and female, with every individual having their own unique mix of traits.
This leads into the Institute's work with transgender patients. Hirschfeld was actually the one to coin the term "transsexual" in 1923, though this word didn't become popular phrasing until 30 years later when Harry Benjamin began expanding his research (I'll just be shortening it to trans for this brief overview.) For the Institute, their revolutionary work with gay men eventually began to attract other members of the LGBTA+, including of course trans people.
Contrary to what Anon says, sex reassignment surgery was first tested in 1912. It'd already being used on humans throughout Europe during the 1920's by the time a doctor at the Institute named Ludwig Levy-Lenz began performing it on patients in 1931. Hirschfeld was at first opposed, but he came around quickly because it lowered the rate of suicide among their trans patients. Not only was reassignment performed at the Institute, but both facial feminization and facial masculization surgery were also done.
The Institute employed some of these patients, gave them therapy to help with other issues, even gave some of the mentioned surgeries for free to this who could not afford it! They spoke out on their behalf to the public, even getting Berlin police to help them create "transvestite passes" to allow people to dress however they wanted without the threat of being arrested. They worked together to fight the law, including trying to strike down Paragraph 175, which made it illegal to be homosexual. The picture below is from their holiday party, Magnus Hirschfeld being the gentleman on the right with the fabulous mustache. Many of the other people in this photo are transgender.
There was always push back against the Institute, especially from conservatives who saw all of this as a bad thing. But conservatism can't stop progress without destroying it. They weren't willing to go that far for a good while. It all ended in March of 1933, when a new Chancellor was elected. The Nazis did not like homosexuals for several reasons. Chief among them, we break the boundaries of "normal" society. Shortly after the election, on May 6th, the book burnings began. The Jewish, gay, and obviously liberal Magnus Hirschfeld and his library of boundary-breaking literature was one of the very first targets. Thankfully, Hirschfeld was spared by virtue of being in Paris at the time (he would die in 1935, before the Nazis were able to invade France). His library wasn't so lucky.
This famous picture of the book burnings was taken after the Institute of Sexology had been raided. That's their books. Literature on so much about sexuality, eroticism, and gender, yes including their new work on trans people. This is the trans community's Alexandria. We're incredibly lucky that enough of it survived for Harry Benjamin and everyone who came after him was able to build on the Institute's work.
As the Holocaust went on, the homosexuals of Germany became a targeted group. This did include transgender people, no matter what you say. To deny this reality is Holocaust denial. JK Rowling and everyone else who tries to pretend like this isn't reality is participating in that evil. You're agreeing with the Nazis.
But of course, you knew that already, didn't you?