I think that it is fair for me to distinguish what I am saying here from what you seem to be saying. 

First, I am not against self-moderated threads, but it seems problematic when a large number of posts that are topical are deleted which causes difficulties following meaningful back and forth.  In the end, those judgements are with the creator of the thread, but there could be situations in which self-moderation crosses into a kind of abusive and seemingly purposely misleading territory.  I am NOT going to bother myself with specific attempts to figure out whether the "remove Lauda from DT" thread crosses into such territory because once my 6 posts therein were deleted, I decided to stop participating or looking at such thread because my time to construct the posts had been wasted when OP decided to delete my 6 posts, which was a step too far from me, so  thereafter, I don't give any shits about what I perceive to be phony boloney discussion points that they want to engage in what I believe to be a circle jerk (based on what I perceived to have been the deletion of my reasonable attempts at contribution to what I had thought to be the thread topic).

Second, on an objective level there are many reasons that self-moderation is likely more efficient then allowing a free range of ideas.  There are posts that purposefully attempt to derail to topic or promote some non-topic issues (aka trolling and shilling) and other conduct that might go over the line in either breaking forum rules or societal rules or norms (such as threats, safety, morally distasteful, and doxing and things like that).  Accordingly, some of those posts just need to be deleted because allowing them is less efficient than deleting them.

Third, I understand that there can be some debate about whether the services of the forum are a public utility or whether there is complete owner discretion.  I think that current state of the world gives a decently large amount of discretion to owners to do pretty much whatever they like.  I understand that theymos does attempt to allow deviance from his personal preferences (in regards to posts, threads, banning/suspensions, assignment of merit sources and moderators/staff), yet I think that he continues to hold a decent amount of discretion to change matters however he wants for almost any reason that he wants or no reason at all.  So in that regard, sometimes, there might be some allowance of topics, posts, member status and contradictions that are not easily explained, and really there is not a duty for theymos to necessarily explain, even though he might chose to provide some explanations from time to time.