@thismoose: When you compare something you gotta do it with something else you know. Since people know something of the same genre, Solo Leveling, they compare this to that one.
Comparing things isnt wrong, whats wrong is comparing things as if there is only one original and everything else is a copy of that original. For example, there is people saying that "I am the Sorcerer King" (another series of the same genre) is also a copy of Solo Leveling, because actually their beginnings are quite similar. Just that IATSK cant be a copy of SL for the simple fact that its older than SL, but people doesnt know that or simply doesnt care, they just wanna trashtalk whatever isnt their loved series.
I always compare Solo Leveling with what happened with Naruto 20 years ago. A series that attracted great numbers of kids and casuals who become hardcore fans (the "narutards") who had the uncontrollable need to diss every other series out there of the same genre. Of course what happened with Naruto was 100 times worse than now with Solo Leveling because when a series becomes an anime it attracts a lot more kids and casuals than web novel or a comic. Those who are old enough will remember that internet forums were Hell those days...
Also, when some work is similar to another one, people shouldnt be so fixated about if its a copy or not, but about if its good or not.