There are more serial serious arguments in the past with self-moderated topics when in the forum, DT members had fight with each other. They even included "additional rules" to prohibited members they don't want to join such discussions.
With self moderated topics, all rules set by OP and OP has freedom to delete posts on his rules and vision. It can be right or wrong rules and vision but if you don't see fit with such topics, don't join them. If you want to discuss but with your own "additional rules", start your self-moderated topics and exclude the trollers ...
I am not against your proposal but with precedent cases, I believe the self-moderated feature will remain like it be.
In self-moderated topics, the OP can delete replies. The option for enabling this is under "additional options".
There are no rules to self-moderation. In self-moderated threads, replies belong to the OP. In other threads, replies belong to the respondents individually. Think carefully about whether you want to reply to a self-moderated topic, as your post may not be given due respect.