Some of these critiques apply to the inherently murderous nature of the Roman gladiatorial games. But early Christians condemned virtually all the entertainments of the Roman mob. They recognized these tribal contests basically served to sow discord, to abuse the human body, and to distract people, especially young men, from things of lasting value.
Indeed, American sports-obsession gives numerous young men an illusion that physical prowess will get them somewhere meaningful in life, when in all but a very few cases, it will get them nowhere. They would be better off in the long term devoting their time to almost any other activity in their school, church, or family than to sport.
Society would be better off, too. Roman political critics recognized that controlling the mob required two things: bread and circuses. Welfare and football. Sports are a drug politicians feed you to keep you placid and distracted. We throw millions of dollars at taxpayer-funded football stadiums and, conveniently, research shows that when the home team wins, so does the incumbent politician.