You may have not set your preferences up for those particular Hubs.
In Edit mode for the Hub click on the Edit Button for the 'Comment Capsule' and check the settings there!
If you want to do it Globally over all of your Hubs you can set it up in your 'My Account' page.
Go to "my account' up near the 'sign out' button, then when your 'my account' page opens, over on the left click on 'comments'.
You should see then an opportunity to set all of you comment preferences globally. btw I have mine all set at 'no'