True, though I think this squeaks through by the nature that a genocide doesn't actually need to completely eradicate a population. For instance, the holocaust did not eliminate all Jews. But they can prevent or disincentivize young people from transitioning; people experience magnitudes higher dsyphoria if they transition later in life, which leads to higher suicide rates. So in effect, this could kill many people.
Also, they can encourage people to remain closeted, making it dangerous or illegal to be openly or visibly transgender. This may not be a literal killing, but you could see it as akin to cultural genocide, which was recognized as a form of genocide since as long as the term "genocide" existed. (It does sound like it could be a neologism, but it's not.)
Well I do suspect that if they (the most ardent anti-trans activists) could find a way to entirely eradicate transgender people they would. Their rhetoric is constantly pushing the overton window to further extremes. At first it was "youth transition should require parental consent," now it's "HRT should be banned even for adults," "trans people should be legally considered their gender at birth," "trans people should not be allowed to travel internationally," "trans people should be considered mentally unstable," "agitating for trans rights should be considered terrorism," "it should be illegal to crossdress in public." I am having trouble imagining any kind of point they could agree is too extreme, but we'll see how it plays out.