How does group's Moderate Posts works?

Hello.

1. When I navigate to "Public Group" as administrator, I can see dropdown list with "Moderate Posts > Pending Posts".
"Pending Posts" is empty because group is public and any member can create post without moderation?
So, I suppose, system shouldn't display "Moderate Posts > Pending Posts" in this case.
In private group users can post without moderation too. So if moderation is turned off (somewhere) it shoud't display this for administrator and superuser?

2. How to enable ""Moderate Posts" for groups?
I can see in frontend group settings only this:

PLG_FIELDS_GROUP_TYPE_SEMI_PUBLIC="Public Group (Require Moderation To Join)"
PLG_FIELDS_GROUP_TYPE_SEMI_PUBLIC_DESC="Anyone can join the group but the user will require the approval from the group admin before they can join the group. These groups will appear in search results."

As far is I understand, moderation for this group type works only for joining group (and not for new posts)?

Thanks.