If I wanted to make the opposite argument — that Lemmy instances should fall under this law — I'd point to the practice of collecting email addresses. Some instances require an email address to create an account. Email addresses make an account more "reasonably linkable" to an identifiable individual.

One could even argue then that the law covers an instance that merely invites users to link their account to their email address, even if it does not require them to. After all, someone looking to target children can look for the most-vulnerable child, not the average child.