Unless it's required of us to investigate a reported instance of abuse of our policies, under standard operation our moderators have no ability to access your private mentions with other members of our Mastodon platform. Due in part to the open and federated nature of Mastodon instances, the Mastodon administrators of other instances you interact with may have access to your data and messages delivered to their servers.
While the connection to this site is encrypted, this is only the data in transit to you and to other servers in the federated network. The messages and data stored in the instance is not encrypted.
This is not a choice of the administrator, but a limitation of the Mastodon platform. While our server administrators do have access to these messages through raw database access, this is not done except under extreme circumstances. Where possible, we will notify you if such processes are taken for data associated by your account.
Additionally, our hosting providers may have access to your data as part of the general administration of the server infrastructure, subject to their own Terms of Service.
You should use Signal, Matrix, or another E2E messaging app for the things you really want to be private.