There are perfectly valid reasons why someone might seek to have a semi auto. I will give you one. Do you subscribe to the idea that hunting with a sub 12fpe rifle always results in a clean kill, regardless? If you do, then you are in a very small minority.
Most of us know that sometimes - and usually due to driver error - a kill is not all that clean, and a follow up shot is required. It ought not to happen, but it does.
When the first two-shot rifles came out, we were told that this was a "good thing", it meant that a second shot in those circumstances could be delivered speedily and before the animal had suffered too much.
The same applied to magazine rifles, having a second shot quickly available was actually a mark of respect for the quarry.
Now, these semi autos can fire off several shots in half as many seconds. How much quicker then, can you deliver the finishing off shot? Is that not actually even more respect for the quarry?