The OP is obviously not a question about whether the umpire got the call it right or not, but about a modicum of respect the coach wants from the umpire. The umpire is there to perform a job and so, to at least some account, should exhibit some professionalism toward the coaches, and vice versa. The umpire calling the coach dude is not being professional, IMO. Can you imagine an attorney going into court and when addressed by the judge saying, "Dude, ....." instead of "Your honor, ...."
Kind of reminds me of an SNL skit years ago with Eddie Murphy as Buckwheat, in court being sued by a prostitute who bought his book "So You Want To Be A Ho" and it didnt work for her. Buckwheat stands up and to address the judge and says: "My Honor, I have one thing to say, the bitch ugly".