baby seals
You just walk up to them and bash em in the head. They don't/can't fight back.
...so, fighting newbs is like clubbing seals. It takes no effort and no talent.
It used to used as a derogatory statement about those that did the clubbing. Folks that thought they were bad-assed, but in reality they were just banging on the new guys.
Fighter Ace with their beginner and intermediate arenas were a prime example. After a certain number of kills, you got booted from the arena up to the next level. Once some folks got to the main level arenas they would auger until their "rank" was low enough to go back to the lower arenas. Back to the ice flows sort of.