IANAL, but this seems wrong.

In an alternate universe, Let’s Encrypt has a chat with someone and then states, publicly, like a speech, that they think that person owns a domain.

In our universe, Let’s Encrypt lets a client open an “account”, enters into a contract with the client (the contract is the topic of this entire post), and gives the client an API by which the client requests a certificate. Then Let’s Encrypt grants the certificate. Maybe the certificate is somehow speech. The rest sure doesn’t sound like speech to me.