What does this spam L2 in fortnite mean?

Many have spam L2 in fortnite in their name

but what does that mean?

L2 is the button you can use to aim at the controller. If you then press the target (L2) button quickly (spamming) then the Zielerfassungshilfe (aim asisst) works better and you can laser one really. Those who have that name call themselves L2 because they always spam L2 and thus las people.