It’s very easy to destroy a specific sub (if it’s not too big and doesn’t have half a dozen mods).

it's like those ddos rings, but works on social networks.

You can create a sub and a Discord group, then ask people in the Discord group to launch a mass report against your competing sub and its moderators. You can use scanners to find questionable stuff that you can report, and more often than not, this will get the mod banned. If the sub doesn’t have multiple mods (with unique IPs, as Reddit tracks fingerprints), the sub is now in the hands of Reddit’s mod team.

Back then it was not this easy, but now with AI and residential IPs you can create lots of fake users and reports etc... and take almost any avg redditor down.