Isn't that what EVERYONE does with old fruit?

Me: "Landis, I cleaned something disgusting off your walls the other day."

Landis: "What?"

Me: "I don't know.....  But it was gross.  It was splattered up in the corner, near the ceiling.  What the heck was it?  And what were you doing?"

Landis: "What color was it?"

Me: "It was brownish - AND GROSS."

Landis: "Oh yeah....  It was a rotten apple."

Me: "A rotten APPLE?"

Landis: "Yeah.  We found a rotten apple....so we threw it up against the wall."

Me: "You found a rotten apple, so you THREW IT AGAINST YOUR WALL?!?"

Landis, (shrugging): "Yeah." 

And he says it with total nonchalance, like "Duh!  Of course I did.  It was ROTTEN FRUIT.  It's what you DO." 

I totally don't get it.  And I can't help but wonder.........Is it my lack of a Y chromosome that leaves me in utter confusion about why that made even a bit of sense?