You are right, “bludgeons” implies that he had some sort of cudgel or weapon, he didn’t—he sucker-punched the kid, which would have been a more accurate headline.
But imagine the headlines if the races of attacker and victim were reversed.
Bludgeoned - definition of bludgeoned by The Free Dictionary
https://www.thefreedictionary.com/bludgeoned
1. club, batter, beat, strike, belt (informal), clobber (slang), pound, cosh (Brit.), cudgel A wealthy businessman has been found bludgeoned to death.