Not sure what the solution is...
Build a capcha value based on some scheme of taking the post's checksum and multiply by present time or somesuch. Make upvotes which pass the CAPCHA scheme, embedded in the blockchain, worth at least twice as much as non-proof of brain upvotes.
An option to prove manual curation and if weighted right could help trending.
The post is a bit 'bitty', but the main point is that the chief stakes are out to rent and are not policing, bar a few kind souls.
Perhaps flag rewards, or a separate flag pool is the option - whether this would be enough to put a dent in some of the shite we see at the top of trending, I don't know :)