This sentence comes from the horror movie <Smiley>

Tomorrow I will search the internet to look for the answer

Perhaps it is a slang

lulz means laughs at someone else』s or one』s own expense

I find a good website: https://slangdefine.org/

"I did it for the lulz " (IDIFTL) is a catchphrase which serves as an explanation for any trolling you do or any internet drama you cause.

So perhaps we can conclude, "I did for the lulz" doesn't mean I did it for justice, it means I did it for the Smiley (the name of the killer in the movie). In other words, "I did it for justice" is a mistranslation