I'm a researcher and conservation biologist. I don't hunt and I would prefer it if others didn't either but I would like to set a few facts straight and hopefully shed some light on a complicated issue.... Despite my personal feelings about killing animals for fun I recognise that trophy hunting is a valuable tool and a much needed source of income for conservationists.
The Princess Royal's argument, which she put forward in a speech to the charity World Horse Welfare, is that people would look after their horses more carefully if they were planning to turn them into steaks and burgers later on. However, in our experience, any animal used for food is much more likely to be treated with disrespect than with respect. Given the regular exposés of mistreated pigs and chickens raised for food, it's absurd to think people would take better care of horses if there were a market for their meat.
The benefits for animals are very significant - anyone who is aware of the infamous Draize Eye test that forces shampoo into rabbits' eyes over several days will appreciate that change was overdue, especially as the non-animal alternative tests often have a better predictive value for actual human reactions.