Dude you're allowed to refuse them, especially if it can be classified as a health hazard. If you had been allergic to cats (as I am) that could've put you in hospital.

The bag smells like cat piss, looks like he let the cat out of the bag.

I feel a little sorry for you because of the few minutes you are subjected to the stench of cat piss.

I feel sorrier for the poor schmuck in Customer Service who will soon get blasted by an irate customer claiming your store sells food that tastes like cat piss!

I once had that happen. I told my customer "diddles went piddles in your bag." She was very embarrassed for not noticing it but we had a good laugh about it anyway.

Oh God, something similar happened to me once when I was doing some volunteering. The lady's bag stank of old Indian food and to my horror, I realised that my hands got covered in days old curry juice.
Had to ask a colleague to cover for me while I went to wash my hands 2 or 3 times.
Disgusting. FYL indeed.

When someone becomes a hoarder (or has a brain full of Toxoplasma gondii) they become immune to the smell of cat pee.

Or maybe the asshole can't smell much anyway.

Either way, I pity them for caring that little.

This is the fault of Capitalism. Unless they can profit from bag upgrading or whatever, a capitalist's goal is to give out the least for the most. Hence cat per bags.

*pee

That must've pissed you off!

How is this an FML for you more than for him?