Exporting Contact List - Confirmed Opt-Out Date Column and Contact Database

Hi, I noticed that after I export a contact list to excel that within the column, "Confirmed Opt-Out Date" there are some dates for a few of my contacts...however these contacts are still in my database to email? Shouldn't these automatically be taken out of your database as to not accidently email them? Or I am I miss understanding this column? 

Thanks for any clarification!