Those comments are removed manually (and the notice posted) when I see the problem taking shape. Typically, well-established sites are able take care of these activities through vigilant community self-moderation. But the Community Team is still considering candidates for your provisional Moderators.
The bigger problem is that, often, it's not actually the comments that are the problem. The root of the so-called "problematic posts" seems to be the need to follow such answers (and sometimes the question itself) with on-going debate and discussion to make them even remotely credible. Point, counter-point — such discussions are simply nature of political forums, and are usually quite welcomed. But simply stated, that's not how a Stack Exchange site works. We want to do something different; something special with this site.
I am in the process of carefully considering what works on this site and what doesn't. The comment-problem you cited seems to be at the epicenter of what doesn't quite "work" in this style of Q&A. I can (and do) remove these comments to keep them from becoming personal chat rooms, but soon we will have to decide what kind of posts deserve such discussion — and send them to any one of the countless forums that have done this thousands of times before.
To follow in the success of what makes Stack Exchange sites "work," we have to be true to our philosophy and simply figure out what type of content we should simply forgo in this format. By doubling down on the pure leaning ethos that we handle so well, we can do something really special and novel here. Review the many discussions raised on meta regarding citations, objectivity, and suitability of content. Contribute to those discussions… and stay involved. Changes are coming for the better.