They think it is a violation of " fair chase" and gives hunters more of an advantage if you can communicate electronically to organize your hunting efforts.
It is considered and unfair advantage.
I consider it safe actually, for instance:
Say your buddy texts you that he is getting out of his stand and will be slowly walking in a certain direction towards you.
In this case you are alerted that the noises you hear and the movement you see in the thick brush may be human, not animal.
I am not one to even think about shooting unless I can identify and have have a clean shot of what I am shooting at......AND in this case I may even postpone a potential shot at an animal if I know my buddy may be walking in the general vicinity......especially during archery with no blaze orange on.
I think this type of communication is beneficial to the safety of hunters and they need to lay off the fairness crap a bit as there are plenty of yahoos that will shoot at any movement in the brush without identifying it so it may actually save a life if Billy Bob could warn Beauergard that's he's a comin' up the knob towards him.