I may be wrong, but I actually think the current move towards codes of conduct and clarity about expected social behaviour should help with these cases.
Being socially dysfunctional (as opposed to being malicious, which is a different problem) is often linked to an inability to pick up the social cues and clues that most people take for granted. A document which clearly explains and gives examples of unwelcome behaviour should help in these cases - assuming people actually read it!
..and assuming those examples of unwelcome behavior are objectively defined. Any room for judgement calls or definition stretching, and you've taken what it supposed to be a useful metric and turned it into a cudgel to be misused.
Example: Wikipedia. The talk pages on that site, especially on politically charged topics, are detailed examples in how one can behave in a destructive fashion and drive off talent without ever dipping into base namecalling.
There is also the opposite, people who are busy communicating, who generate lots of noise and never do anything.
So yes, merit should be defined as getting useful things done with rough consensus and not as brilliant code that then split the community.