find an alternnative to pointless killing,
A. Protecting people from an aggressive animal isn't "pointless".
B. Guilt-tripping people who aren't willing to have their chicken keeping turned into a time of anxiety and wariness instead of joy and peace is silly.
C. Keeping a known-aggressive animal that has drawn blood is a legal liability if it ever hurts someone else.
D. Polite, well-behaved roosters are killed every day because the owners either can't have roosters or have more than they need. Keeping an aggressive one instead of adopting a better one is truly pointless.