Since we spay and neuter the cutest pets to adopt them, we are slowly evolving the cuteness out of them, amirite?

I think you're cute, OP ✂️

I think we do that regardless of cute

Not exactly. They themselves may not breed, but a close relative of theirs will as part of breeding programs to ensure they don't extinct. This 7s how selfless genes get passed down, hence why some animals are generous to their own kind dispite the downside of giving away your food.