Seems like not all those calls are from AdRotate (pro) 🙂
AdRotate (Pro) has no table user-list, nor does it use such a table.
Anyway, to lessen calls like that, don’t use dynamic groups (or less of them).
In recent versions of AdRotate (Pro) the admin-ajax stuff has been improved to work more efficiently. So also make sure you’re up-to-date.