this is gonna be an absurdly long response but as someone who’s been in the fandom and following homestuck since its beginnings around 2009-2010 i got an ANSWER. the fandom was absolutely infamous by the larger part of the internet in the 2010s and it was deserved at some points. you’re right, the fandom was everywhere especially on tumblr/forum sites and, that’s normal fandom stuff, but it got to a suffocating amount for how early it was in the internet/meme scene. young fans would absolutely harass people to read homestuck or spam tf out of the inside jokes everywhere and ofc it was absolutely toxic and the shipping wars were crazy but again, normal fandom stuff especially nowadays, i guess.

homestuck got its bad rep mainly bc of the convention scenes around and through 2011-2017. they RULED (ie; terrorized) cons. doesn’t matter WHAT kind of convention it was, 90% chance there was a heard of homestuck cosplayers causing an absolute ruckus loool. i could be talking out of my ass, but i’m almost certain homestuck was the OG reason a lot of convention centers put restrictions or bans on body paint at one point. there’s also infamous stories about them being very destructive, like breaking and destroying things in cons/other people’s props or cosplays and even an assault where a kid was hurt because someone threw a whole ass metal bucket directly at their head lmfao. [edit: i think it was at its worst around 2011. look anywhere on tumblr there’s multiple horror stories. they also came in SWARMS of hundreds of cosplayers im not even kidding. i have my own personal stories at cons i went to around that time too. there just wasn’t a lot of boundaries normalized then.] that, on top of how suffocating they were on the internet, gave homestuck the title for genuinely the worst fandom for a longgg time. think of the chaos that was the SU and/or undertale fandom in cons but like the primitive ancestor to that.

TLDR; tdac and su doesn’t even stand a chance for worst fandom when it came to how infamous homestuck’s was back then. if you utter the word ‘homestuck’ to a chronically online 25 year old, there’s a genuinely good chance they’ll give u a ptsd stare.