Probably says a lot about how much brutality we've engineered out of daily living. I recall having a visceral reaction to hearing about the kittens as a child, and I imagine it's fairly natural to feel that way. I'm glad I lived in a time and place where that kind of desensitization wasn't necessary.
Unfortunately it is still fairly common in small villages (in Hungary at least - which is quite poor outside of its capital). Spaying is expensive and cats do produce plenty of offsprings, and it is not even like with dogs that you can just keep inside the backyard..
(Though what I heard about is not drowning, but slamming them hard to something :/)