Can you be more specificabout what you're trying to accomplish? Mandatory to be included on a page? (that would be by setting up a template) or mandatory that a site visitor enter a comment?... it's not clear.
What version of AEM are you using?
You're referring to the Communities (/libs/social) component?
Its looks like a strange requirement to have a comment as mandatory !!
As @Janice mentioned, can you elaborate on your use case ??
Please explain more your use-case. What is that you trying to achieve? if someone enters the page then they have to comment? Or that you want it to be part of every page?
Thanks and Regards