Are you sure? Someone broke into a Hetzner data center and a Linode one, physically intercepted the Ethernet cables for jabber.ru, and got certificates signed on their behalf.
Lesson to learn: Let's Encrypt does not protect against MitM by a state-level actor, unless you take precautions. *let's assume network admins won't MitM your server for personal vengeance reasons
But S in https stands for secure, or ? /s