Protein itself is not going to make anyone fat, with the high cost of digestion protein carries it's the last macronutrient to ever be stored as body fat. You have to look at the totality of what you are eating thats making the protein to cause you to get fat. Too much protein will cause other macros to be stored as body fat if those macros are taken in excess. It's very easy, eat more protein burn less carbs and fat for energy, burn less carbs and energy = storing more adipose tissues. Learn to time your meals and macros and eat according to what you just did and what you are going to do and you will and you will be surprised at how fat you don't get!
Of course, hormones, training frequency, volume, metabolism, genetics, general lifestyle, all factors in. What works for one person and is true to one person can be completely wrong and false to another person. And at the end of the day they both will argue, however at the end of the day they will both be right!