With the comntr widget you can add comments to your page. Add this to your index.html:
Your filter tag: FooBar
Your public key:
Anybody can post comments, as long as they can solve a basic captcha, only you can hide comments, as long as you have the proper private key.
An advanced user may use the the comntr extension or just remove the filter tag from the iframe URL to see hidden comments.
If you want to use this comments widget on your site, contact comntr (dot) io (plus) github (at) protonmail (dot) com for details.