Musk believes in free speech, which means he believes in the right to question and debate so-called "authoritative sources." The US government and Big Tech policies related to COVID were arbitrary. On Twitter, users were suspended for spreading any information that wasn’t blessed by the establishment. This is a win for freedom of speech.
Allowing disinformation isn't promoting free speech, it's hindering the public's ability to receive life-saving medical advice. Under Twitter's previous policy, experts were able to flag harmful speech and protect the uninformed from dangerous disinformation. Under Musk's new policy, and amid another rise in COVID cases, those safeguards will be gone, and the public square will flood with harmful public health recommendations.