This is because 'to hit' can of course mean "to punch someone" in English, and then 'ler' is the present tense of the Norwegian word for "to laugh". Put these words together and it made some amount of sense to me to imagine old "hit-laughs" as someone who hits people and then laughs at their pain, in other words a bully, a sadist, or otherwise a cruel villain.
When I was a kid I liked the band Gas Pump and their groovy electronic music, especially songs like "One More Time" and "Harder Better Faster Stronger". I wondered why they had chosen such an unusual name.