Ive tried to rationalize in my head the reason they may NOT be allowed for tracking and two things (one of which is semi-valid) pop into my head.

1) The law makers may THINK that hunters would be apt to take a less than optimal shot knowing they can use a dog for tracking.
2) The law makers may THINK that hunters would abuse the law and get into the gray area of where a dog may be off leash, jump a deer, and hunter shoot it, and it not be the deer in question.

The last one can be fixed by a leash law. The first one, idk. I think they should be LEGAL. We owe it to the animal to find it whether it was a freak accident or a poor judgement.