I tried filters on other platforms, the results weren’t that good. Yes, you blocked a word, but people often use images with text for some reason, and filters don’t work with them.

What are we going to do about it?

Nothing. People move to reddit and discord for a reason. If forums were worth saving, this problem wouldn’t have existed.

by ditching the Karma farmers

How, exactly? Decentralization aside, lemmy is a reddit clone, but on a smaller scale. The same human psychology that drives reddit also drives lemmy. I think your assessment is more applicable to mastodon because there you really have to figure out how to fill your feed with content.