I just saw an advert trying to sell cat food especially for neutered cats. The tagline was 'it helps your cat live life to the full'.
Getting your balls cut off so you lose all sexual desire does not exactly match my view of 'living life to the full'.
I suppose they couldn't have told the truth: 'Now that your bollock free moggy is lying around the house looking depressed and lethargic, he's probably gonna get a bit fat on normal cat food. So why not piss on his razor cuts further by taking away another of life's pleasures and give him less tasty cat food...you know, to punish him'.