Apparently, you have never seen how important a pet is to someone who has nobody else. I'd say there's more of those "least important life forms" around that have saved the sanity of the old, injured, sick or alone than you'd ever think. Similar benefits accrue to pet owners in general.
http://en.wikipedia.org/wiki/Animal-assisted_therapy
Also in turn, the act traumatized the owner of said kitten, which qualifies as an assault in my book. Even treating them as aesthetic property, having someone violently destroy them in front of you is disgusting and criminal.