The guy may have mental issues.
Sounds like some neighbors were feeding some feral cats and the guy got tired of cleaning crap off his balcony.
Feral cats are filthy disease carrying varmints that are devastating to wildlife and to people's pets and need eradicated.
And you feel that way with feral dogs?
The only difference between a feral cat and a family pet is a caring hand.
IF so, he should have used the ole anti-freeze in a bowl trick rather than shooting at another's balcony.