Because they can shoot 100 yards? Or because they are less lethal and ethical to hunt with?
I don't need a crossbow, but I have no problem with crossbow hunters. They rarely take an animal past 40 yards without perfect shot placement, and it makes people who are too lazy to practice archery (not nocking disabled individuals, I'm talking people who would do fine shooting a bow, but have no interest in practicing) make better shots resulting in less wounded animals.
I've never run into a crossbow hunter in the middle of nowhere public land where I hunt. I don't think they are taking anything away from me during the season. There are several guys in my hunt club on the private lease I hunt who shoot crossbows. They'll find the deer no matter what weapon they have. The crossbow has resulted in more kills and less "we'll maybe he'll survive to next year."
For this post, I agree that if you're going to get the shooting stick for a bow, just get a crossbow. And if your going to get a crossbow, there is still a seat available for you next me in the truck on our way to a hunting spot. I just want people to hunt!