The question is whether it's okay to shoot first at a gang of heavily armed criminals, or whether you have to attempt an arrest first.
Importantly, this isn't poaching. This was lawful collection of elephants. Morality aside, this does provide funding for cash- strapped nations and some of that funding goes to protection of stressed animal populations.
Yeah let's not do that.
I personally dislike zoos and don't visit them. At the same time, I'm not comfortable telling you how you should feel.