Currently all comments require resolution, i.e. if they are not resolved, then the event satisfies the filter condition "has open comments".
Some types of comments may just be annotations or notes that don't require follow-up action, or are intended to flag an event for later retrieval (when it's possible to search and filter on comment types).
It should be possible to configure a comment type that doesn't require resolution, i.e. when added it is already resolved.