The only reason that " Nonresident guided sheep hunters are taking 60 percent to 80 percent of our sheep in some areas", is because those areas are very remote and involve expensive bush flights that non-resident, guided hunters are more willing to pay. Many resident hunters hunt areas that are more more easily accessible. Resident hunters can compete on equal terms if they are willing to cough up the money to hire an air taxi. 
Nothing nefarious going on here that I can see. I would really like to know what the letter writer's true motives are.