Speaking as a former default mod:

Reddit doesn't have the tools to ban anything. They can play whack-a-mole and hopefully wear out their adversaries or drive them to another site. They can hunker down on the knowledge that what they do takes less work than what their adversaries do, which hopefully balances out the fact that they're outnumbered a thousand to one. They can ban one community and another and another and another and hopefully the goons get tired of the game. But every time they try this ploy they show their limits. Meanwhile their adversary learns their game and learns what it takes to make them capitulate. And as the scandals mount, they get more press. The game becomes more fun.

And all the reasonable people have been driven away, and what's left are the jihadis.

At its fundamental core, Reddit does not have the architecture to control the conversation. Upvotes and downvotes are a crude and brutal tool that favors easy-to-digest content and despite the fact that criticism has five times the impact of praise Reddit counts both equally.

It's an architecture that weaponizes enthusiasm and inattention at the cost of thoughtfulness and insight, while also heavily favoring dissemination over digestion. If virulence ("virality" - fuck you marketers) is the aspect of social dissemination we're watching these days, Reddit was engineered to be ebola back ten years ago. There have been adaptions and modifications that have allowed it to keep its carriers alive for a while but it's a fuckin' brutal organism. It wasn't designed to be controlled. It was designed to spread. It was designed to shape its own destiny through competition and extinction and there were never many controls built in to steer it. And what controls do exist lack any sort of utility in dealing with a persistent threat.

Most of us have long since given up.

If there had been any thought whatsoever to social media, Jack Dorsey and Alexis Ohanian and Mark Zuckerberg would have considered for a minute or so just how easily their little petri dish projects could be weaponized. But they didn't. And here we are.