To clarify (in case it isn't already self-evident); Elon isn't trying to say he thinks autistic kids should be sterilised (a horrible message), he is saying that he thinks that trans people don't exist, that people who identify as trans are just autistic people who are confused and that therefore support for trans people to transition (and in some cases become sterile as part of that process) is in fact just support for sterilising autistic kids (also a horrible message. But a different horrible message to how it might appear. So... I guess it's helpful to know exactly which awful thing Elon is saying here?) Either way, by sharing it, he ends up actually amplifying both messages and who knows what his actual values are or why he would want to endorse this meme. I suspect even Elon doesn't entirely know the answer to that.