While shouting from sports announcers is kept to when it's arguably appropriate, the amount of gratuitous shouting increases the further from the actual sporting event the "sports show" happens. Interviews with athletes outside of the game or official announcements become louder as the relevance of the questions decreases. "Sports chat" shows, generally consisting of a small group of men (and sometimes one female) talking about the statistical and business side of sports, are almost as bad as sports interviews. Sometimes gratuitous harsh language is thrown into the mix, just for edginess or something.
Legitimate example of No Indoor Voice: Hall of Fame basketball announcer Dick Vitale. This is not so much a case of always shouting (although he does plenty of that, too) as just a case of having an unusually loud regular speaking voice.