I think the internet vigilante has gone too far, wishing someone pain and death is wrong. This man did something awful; really, really awful, and he should have consequences for that. He should be charged. Publicly shamed, maybe (I tend to not like public shaming either, because sometimes it is incorrect information, or innocent people involved, like the people who worked for this man, or minors). Should he be physically harmed, killed, had what he did to the lion done to him - no. Two wrongs don't make a right, and anyone who harmed this man would be as bad as the man himself. Revenge is not justice.
I would like to see him extradited and face the consequences in Zimbabwe.
I do think this incident has brought out the worst in society. Yes, it has the whole lot of awfulness - protected animal, in unnecessary pain for hours, "senseless" kill (as in, the meat, fur etc. we're wasted, unlike I'm some hunting), but many animals on our tables at night have also been poorly treated, and many are every day, in awful conditions that the law allows. I'm a former vegetarian, love animals, and know the source of all meat that I consume, the conditions the animals are kept, what they're fed, etc. I would say the majority of people don't, and likely don't care or want to know. Because if even half the people outraged by this incident would make a fuss, laws would change to mean ALL animals are well treated, and animals for consumption all humanely kept and killed.
Sure, this wasn't just any lion, but what if it was? Is one lion really worth more than others? Because he's tame, or wild, or known? Hunting for entertainment should be outlawed globally, and we should be fighting for the ethical treatment of ALL animals. I hope once the outrage dies, that this is what will come out of it, not people wishing death, harm, or misfortune on someone.