There are a few underlying issues here.
There is a lot of denial about the nature of the intellectual bell curve. The majority of people are not that smart and cannot make thoughtful contributions to most discussions. The majority of people will at least some of the time lose decorum and make vicious personal attacks when they perceive themselves as being threatened or as being wronged. Upvoting and downvoting is an action, and action requires motivation. Thus, unless an audience is especially smart and valuing of rationality, comments are most likely to get upvotes when they provoke an emotional reaction.
To have a high quality discussion board you must have a critical mass of reasonable, smart people. You must avoid letting in the hoi polloi. And you must quickly ban users who make dumb comments or violate decorum.
However, most internet business models are based on advertising. Advertising revenues are based on eyeballs. And a normal stupid person's eyeballs are worth just as much as smart person's eyeballs (perhaps more, the smart person probably has adblock installed).
Thus the central conflict. Business models are based on making it as easy as possible for normal people to get engaged in the platform. But the result of normal people getting engaged will be vicious and unsavory content. Also if it is easy to create account, then it is easy to switch accounts if one account is banned. So it becomes impossible to silence the unsavory users.
I think that ultimately Reddit will end up as sort of the Wikipedia version of a newspaper. All pretense of being free speech or democratic will be dropped in the major subreddits. Rather it will be a media site on a variety of issues that is mostly top-down, and controlled by the actions of entrenched, established users and moderators.