As far as injured dogs, I don't believe any sane person wants to see their dog injured. But sometimes that's a possible outcome in the sport/line of work.
I'll never forget the day that a 350 lb boar got a tusk up under DD's cut vest basically impaling him. Even though he was wearing a cut collar and vest, he was still injured. He got flung off, and I ran to grab him, while the other catch dogs contained the hog (there were several of us that day), and I picked him up and rushed him to the car to get him to the clinic asap. He ended up having a punctured lung, and was pretty seriously injured. It took months of recover to get him healed up, but before you knew it, he was ancy and going bezerk wanting to do something. After taking time off to heal, and some more time off to get back into shape, I put him back in his vest and collar and we went hunting once more. He loved it. He was a dog that had to have a job, and he enjoyed hog work. No, I didn't like seeing my dogs injured and having to scratches and wounds and suture/staple them up, but that was a risk we all took. I did my best to make sure they were in tip-top shape, properly nourished, and wore protective equipment. But I'm not going to bubble-wrap my dogs and keep them on the couch while serving them dinner on a silver platter all so they won't get hurt. Dogs get seriously hurt playing fetch. I'd rather let my dogs live, and do something they enjoy, than cause them to be constantly frustrated and agitated from lack having something to do. Some may be content with obedience. Others are not. Some have no desire to go after hogs 5+ times their size, so it's wonderful to find another venue. But I won't use the risk of injury to avoid working them.
That doesn't make me love my dogs any less, nor does it make me a lesser dog owner than someone else.
Heck, a vet I worked with had approx. 55 Running Walker Hounds that her husband hunted with. He's a big hunter, and much of their life revolves around it (well, his mostly). Their dogs are working stock. They don't sleep in comfy dog beds in indoor kennels. They aren't fed homemade dog food. But they also aren't neglected or treated cruelly in any way, nor are they loved any less. But face it: not all dogs are pets. Nor should they be forced to be seen that way.