Of course we can think of many nonviolent activities. But is that the standard of comparison? Is that a realistic alternative.
Appearances notwithstanding, it seems to me that contact sports restrain violence by channeling and regulating natural masculine aggression. Contact sports have rules which limit the violence.
If male aggression is an innate masculine trait, then attempts to suppress it will be counterproductive. The attempt to systematically suppress a natural irrepressible trait will simply divert the trait to a more dangerous outlet.
In place of contact sports, you’re liable to have more beatings, knifefights, gunfights, urban warfare. Gangs take the place of teams.
Of course, absent common grace and special grace, any social activity can degenerate.