Twitter's TOS[0]: "To avoid confusing others about an account’s affiliation, parody, commentary, and fan accounts must distinguish themselves in BOTH their account name and bio."

Ethan Klein's account wasn't noted as a parody in its name. Its name was Elon Musk.

Klein's account had Elon's account's profile picture and name, and had a verification badge. I think its totally sensible that the account got banned.

[0]https://help.twitter.com/en/rules-and-policies/parody-accoun...