Walmart

I recently purchased a box of the above cupcakes on tuesday of this week which would be the 5th of January and the first cupcake I ate out of the box on friday was discolored and didn't smell right or taste right after I chewed into it. So after eating it I checked the expiration on the box and was slightly shocked to see the date of August 13th, 2020 which would be almost five months ago!
Having worked in food service for 15 years of my life I couldn't help but wonder what bumbling idiot put this on the shelf WITHOUT checking the date on a product that should have been thrown away a loooooonnnnnnggggg time ago!
Thank God I didn't get sick or I'd be REALLY pissed. Please help me understand this and now I have to check every damn box of food myself when I buy ANY product in your stores now which I really hate doing since you pay people to do that for the public... don't you?
Irate customer # 267 S Famiano, PO Box 80755, San Diego, Ca. 80755