Comment made by Bronson as stated in the Trivia

On the first day of production, Charles Bronson got angry about a delay caused by a late transport truck carrying cars necessary for the scene that was to be shot. Finally, he yelled to director Richard Fleischer within earshot of the entire crew, "You know what this company needs - it needs a European first assistant and a European crew!" The crew was so insulted by this remark that at the end of the day, they told Fleischer they would be leaving the production. They were persuaded to stay, but for the rest of the shoot they never spoke to Bronson unless they absolutely had to. Later in the shoot, Bronson commented to Fleischer, "I just don't understand it. Nobody calls me 'Charlie' on this picture. They only call me 'Mr. Bronson'."

Why did they feel so insulted? So, that was worst thing you would say to someone? Also "for the rest of the shoot they never spoke to Bronson unless they absolutely had to." Seems like they are overreacting.