Currently there is no option to disable comments in Documents and Media Portlet Configuration.
It is possible to disable the comments for other portlets (e.g.: Wiki portlet).
Similarly, it would be beneficial to have:
- Enable/disable option accessible from Documents and Media Portlet Configuration
- Or from Control Panel/Configuration
While there is a portal property to disable comments on DL File Entries (dl.file.entry.comments.enabled=), this cannot be limited to sites or portal instances.