So here's the simple breakdown.
I used the built in Smart List in the Email Program to filter out leads, but when I go to view "Leads", I still see leads I filtered out.
So I created a separate smart campaign and used the exact same filters and logic, and that populated a correct list just fine.
So what am I doing wrong? No matter how many times I tell the smart list in the email program NOT to include any email addresses that contain XYZ, it still does.