The new book reveals that Igor was regarded as obstinate, petulant and even foolhardy at times by some of his fellow hikers, so perhaps occasional rudenesss was also part of his nature.
Page 135, referencing one of the search team members, residing in a base camp tent.
From Grigoriev's diary
"We were talking about the deceased througout the whole evening. About why they had pitched their tent on the mountain, etc. It was said that Igor Dyatlov was very ambitious, prone to domineering. At one point he suggested to his group to cross from one bank of the river to another without any reason - with no reason at all. At one point the people were so outraged with his behaviour that they would not follow his orders. Then he retreated and declared a hunger strike. He was a good and diligent rank-and-file member of the group. All mistakes were attributed to him. Two people who happened to be with him spoke about it in particular. Kikoin as well spoke negatively about him. He said that it was stupid, that the group left at 3pm when it would get dark here in about an hour and a half, or two."
I have wondered, given Igor's bladder was fit-to-burst, if he may have had a physical problem affecting his behaviour, and potentially even his decisions, such as a bladder stone or urinary tract infection, which would prevent him urinating effectively, in which case his kidneys would be overloaded, particularly dicey in the extreme cold, his bloodstream full of unfiltered toxins from food digestion, and his blood pressure rising due to too much fluid in his veins. When the same happens to even the mildest little old lady it can affect their behaviour, even swearing and becoming aggressive.
It may have been either a physical or psychological thing.
Elsewhere in the book it does briefly confirm that Igor had hoped to take Yuri D's place.