"They charge for that kind of thing in the States?"

Slight hair to split...

I'm NOT in the "States"

And yes, our Humane Society charges for stuff like that... The Humane Society needs money to run... and this is one of the ways they make it...

"I think you would harbour ill will toward people who did something like that to you."

It's a cat... they have a 2 minute memory... Only slightly longer than a goldfish...

There are lots of organisations who catch/fix/release wild cats... Especially in areas where there are too many cats to 'home' out... and where they're doing their job of keeping the local vermin under control... By catching and fixing as many as they can, they help keep the cat population under control as best they can... And fixing a wild cat does precious little to its behaviour... So it's not like it's a major "blow" to kitty...