Specifically the charges are cyberbullying. Both Musk and Rowling used their huge media power to try to frame Imane Khelif as a trans athlete with the purpose of disqualifying her in the games. Both the evidence and the Olympic rules would suggest that this is not the case. Imane Khelif was born as a woman, raised as a woman, who just happened to be a very good athlete. Personally, I do not support allowing trans athletes to compete in women's sports. However, I think that framing an innocent person to advance an ideological agenda, as Musk appears to have done, is far more serious as an offense.
Imane Khelif looks somewhat masculine, then again so did about half the nuns who raised me as a child.