The villain (protagonist) who is shown to be extremely cool, get a hot goth girl, be worshipped as god, and then given a very bittersweet ending. If the intention was to make the teenage readers not like Light then they failed, as evidenced by every comment section ever on the subject being filled with Light defenders who believe his initial quest was righteous and he just got off track. That killing “criminals” en masse is justice.

Many saw the moral as “absolute power corrupts” and not “who gave this fascist little shit god powers”. Of course we can see that his “downfall” was inevitable since second 0 he was acting like an unhinged reactionary incel, but there are many who instead see it as a legitimate Icarus/Lucifer/downfall story where he was correct at the start - similar to how Lucifer had a point in the war in heaven (that god should save all souls instead of letting some fall into sin).

Lucifer’s original point at least had in its core a good intention, Light is like if Lucifer started out evil in Heaven already wanting to “punish” all the evil souls cause he was just inherently a bitter little shithead, but all the Light fanboys fail to make the distinction because they see being a bitter little shit as a positive thing.

I actually have a terrible hot take about goblin slayer being good axtually.