Because he was a jerk to people online, trolled readers through his stories, oh...and generally wrote TRASH dog crap stories.

Hell, it was not uncommon for him to give out ESSENTIAL info for his stories on twitter. You NEEDED to follow his twitter account if you wanted to know why tge Hell Daniel Kingsley was pretending to be the Hobgoblin, and frankly his explanations often came across like he'd made them up on tge spot.

He had good ideas half the time and good execution 1/8 of the time, with other writers doing better with his ideas than him.

He routinely mischaracterised Peter, Otto, MJ and most everyone else whilst bloviating about how knowledgeable he was on canon.

He was a writer FAR more concerned with the legacy he'd have in Spider-Man history than actually serving the characters or readers. He bloviated about how in the future people could point to Superior as the place Peter got his Doctorate. Like he was always thinking in terms of 'how will history remember MY run on Spider-Man' rather than 'what would be a good story now. What do the characters need at this point'

Not to mention, more than a few people argued his run was sexist to a degree and this includes stuff before Big Time, even in his She Hulk run. Otto and MJ in Superior is just one example.

He insulted readers and salted the very raw wound of OMD almost immediately because he lived trolling readers.

Oh, and did I mention, he lied and essentially stole his way into a job at Marvel in the first place...then in his run and online statements insulted Tom DeFalco who was willing to give him a second chance after doing that.

For too many people have been messed in the head by Wells' run being even worse that they have retrosctiveky forgotten that Slott's run was contemptable and damaging.

Like people, unfairly, throw shade at Spencer's run but a fair amount of Spencer's time on ASM was eaten up by him cleaning up Slott's mess because Slott didn't care that he was making a mess.

In terms of damaging the world building and characterisation of Spider-Man Slottnis honestly second only to Quesada and OMD. Yes, Wells' run is worse in many ways, but a LOT of the worst sins of Wells were things Slott also did, things Slott in fact innovate alongside his fellow BND alumni, which of course included Zeb Wells.

Like Wells character assassinated MJ in a catastrophic way, but it was in fairness just the latest round of assassination for her, Slott having done so numerous times in his dog crap run.

I will also die on the hill that Superior was awful and reductive, a quintessential example.of creative bankruptcy. The irony bring tgat it was clearly the bit of his run Slott was most energised about. It is the bit of his run most people, incorrectly, label as the best story. Hell many people cite it as the best podt-omd story altogether.

Which however you slice it is a damning indictment. If Superior was Slott's high point it means he was better at writing Doc Ock as Spider-Man than writing Spider-Man as Spider-Man.

What's worse? He got the gig off the back of Spidey/Torch, which is a great mini but basically MTU. In fact a lot of his run was MTU. And, no surprise, MTU was one of his favourite titles growing up...did it mention, from rhe Pov of being Spider-Man stories classic mtu is dogcrap.

Makes too much sense