Great. I support freedom of expression as well. Everyone should be able to live free from persecution.
In a liberal society, with freedom of speech and expression, we also have this thing called the 'marketplace of ideas', and GI doesn't stand up to the slightest scrutiny in there. Gender identitarianism is a quasi religious, unfalsifiable metaphysical belief system; secularized gnostic gender/body dualism, that reeks of late stage capitalism luxury belief. It demands denial of reality, sex in particular, and posits "gender identies" that are real. It's It's unmoored from empirical reality. "Magical thinking" in clinical terms.
Denial of reality is not a solid epistemic hook to hang your intellectual hat from. Adoption of a trans identity did not make the killer more resiliant, more healthy, or less antisocial. It made him weaker, broken, vulnerable to and more prone to violently losing his marbles. His journal entries are haunting. He shows why we don't affirm delusions. He used his as justification to commit unspeakable horror.