That's because Palmer is not so different from thousands of other wealthy trophy hunters in the US and throughout the world, who hopscotch all over the earth in luxury and comfort to kill the largest "specimens" of the rarest mammals. Baiting, jacklighting, shooting in parks or fenced areas, with guides even drugging animals to allow these aging men to shoot these magnificent creatures, are all par for the course. That's their hobby, albeit a warped, selfish, and inhumane one. It's going on every day in the remote reaches of the globe, enabled by professional guides and wildlife officials who are at least complicit if not directly on the take from rich people with a mania for killing the most beautiful creatures in the world.
As for Zimbabwe, this is a country long plagued by terrible leadership in the post-colonial era, and it is a nation deeply corrupted, autocratic, and ruthless when it comes to the treatment of wildlife. Walter Palmer went there because there are too many officials there ready and willing to sell off wildlife to the highest bidder. Good for them for seeking extradition this time - but let's just not be fooled into thinking that this is a principled, forward-thinking government at work.