You nailed it exactly with this:
There's never been any clear consensus about whether/where to draw a line on the latter.
Without a clear consensus, it's not possible to program blockchain-level solutions or to even build bot-solutions. In many ways, we also have to consider cultural differences in opinion on what constitutes abuse, spam, and "valuable" comments and posts. There's a lot to figure out with regards to clear community-driven norms which stake holders and new users alike will support.
We don't have to define what is or isn't abuse to get a fix into the blockchain. We can have solutions that make it easier to counter abuse while still allowing it to be 100% down to subjective stakeholder opinion.
Consensus can't be built if we don't talk about it. Would join a discord chat for whales and senior users if I made one?