Survey comments that an admin has marked hidden will be kept hidden on the live site. However, these comments will not be automatically excluded from appearing on a dynamic report. To keep these comments off your dynamic report, follow these steps.
First, ensure that the comment is indeed hidden. Navigate to the Comments tab of your survey and ensure that the red Hidden icon is active; click it if not.
While this should successfully hide the comment from appearing on the live site, the comment will still be visible on the dynamic report.
To change this, hover above the comment section to expose the controls and click the Options button.
In the "Comment display settings" modal that opens, toggle off "Show comments hidden by admins."
There are also a few other settings here worth considering, such as the setting to "Show comments hidden due to profanity or toxicity" and to "Show comments marked 'Hidden' or 'Private' by the participant."
Make your adjustment(s) and click Save in the lower-right corner of the modal.
The comment that was marked as Hidden should no longer appear on the report!